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Home / Gear / Jackets / Insulated Jackets / Synthetic Insulated Jackets

Atom SL vs Proton FL

Last updated: November 9, 2022 by Canberk Koksal

  • This article is revised after Arc'teryx FW23 update. 
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Proton FL.

I've been publishing in-depth helpful guides to almost all Arc'teryx jackets for more than two years now (see full post list at the bottom). 

Now that the summer is here, let's take a look at how the differences between Proton FL vs Atom SL play out. 

Atom SL (Super Light) and Proton FL (Fast & Light) are the two most breathable, least warm alternatives you can find in Arc'teryx's insulated jacket line-up. 

They're both best suited for chilly summer and/or spring mornings, followed by a high output activity (primarily rock / alpine climbing).

  • Latest on the blog:
  • 13 Mar 2023: I've been to Pfander and floodplain forests with my Nuclei SV
  • 13 Dec 2022: Arc'teryx Alpha Parka Review: The most impressive jacket of all time
  • 8 Dec 2022: Arc'teryx ReGEAR: OutdoorCrunch exclusive promo code!
  • 7 Nov 2022: 2023 Thorium Hoody is in - as well as the new Thorium Parka (yes, parka)
  • 2 Nov 2022: Beta Insulated Jacket: Pit zips AND two way zipper!
  • 7 October 2022: Proton Hybrid Hoody is live! The ultimate do it all?
  • 5 October 2022: DropHood vs StormHood: Pros/cons and best uses
  • 5 September 2022: Reviewing Arc'teryx Fall Winter 22/23 Gear
  • 5 August 2022: 5 things all Arc'teryx newbies should know
  • #A sidenote here: Arc'teryx's PDF guide to jackets is GOOOLLLLDDDDD. Absolutely check that out too if you're interested in buying one. 

These jackets are more alike than they're different. 

  • Proton FL is slightly warmer, slightly more breathable, slightly more durable and comes with an inch longer hemline 
  • Atom SL is more wind resistant 

Short answer is that unless you'll be using the jacket under windy conditions 90+% of the time, I'd probably recommend you to get the more versatile option, the Proton FL. 

Warmth

Neither of these jackets will provide substantial warmth. Like I clarified earlier, they aren't even designed to do so anyway. 

Proton FL is insulated with Octa Loft throughout the entire jacket. The Atom SL, on the other hand, is insulated with Coreloft Compact only around the core, which holds it warmth back. 

I'd recommend you to take a look at the lowest temperatures they're expected to be worn comfortably by an average person (both are positioned at the bottom): 

  • Arc'teryx Jackets: Temperature Ratings

NameEst. Temp (F/C)ReviewPit venting?Stuffs into itself?Two way zipper?TypeFill PowerFill Weight (grams)Fill Volume (FP x FW)Synthetic Insulator (SI)SI AmountFace FabricActivityFitWeightLength (CB)
Arc'teryx Alpha (Men's - Women's)-18/-28ReviewNoYesYesDown850296251,600Coreloft90 g/m²N30r 2L GoreTex InfiniumClimbingRegular805 g / 1 lb 12.4 oz86 cm / 34 in
Feathered Friends Khumbu-17/-27NoYesNoDown900378340,200Primaloft Gold200 gPretex Shield XTAll RoundRegular960 g / 2 lb 2 oz?
Arc'teryx Ceres SV (Men's - Women's)-15/-26ReviewNoYesYesDown850240204,000Coreloft?Arato 30All RoundRegular880 g / 1 lb 15 oz86 cm / 34 in
Mountain Equipment K7 (Men's)-13/-25NoYesYesDown800300240,000N/AN/A30D DriliteAll RoundRegular820 g / 1 lb 13 oz76 cm / 30 in
Rab Positron Pro (Men's)-13/-25NoYesYesDown800300240,000N/AN/A40D Pertex Quantum ProAll RoundRegular740 g / 1 lb 10 oz85 cm / 33.5 in
Arc'teryx Therme SV (Men's)-11/-24ReviewNoNoYesParka750211158,250Coreloft60 g/m²2L Gore-TexAround TownRegular1.072 kg / 2 lb 5.8 oz96 cm / 37.75 in
Patagonia Grade VII (Men's)-11/-24NoNoYesDown800335268,000N/AN/A1.2 oz 15 & 20D Perfex QuantumAround TownRegular743 g / 1 lb 10.1 oz83 cm / 32.5 in
Arc'teryx Firebee AR (Men's - Women's)-10/-23ReviewNoYesYesDown800225180,000N/AN/AArato 7 & 10All RoundRegular680 g / 1 lb 8 oz79 cm / 31 in
Mountain Equipment Exo (Men's)-10/-23NoYesYesDown800265212,000N/AN/ANylonAll RoundRegular770 g / 1 lb 11.2 oz79 cm / 31 in
Arc'teryx Thorsen (Men's)-7/-22ReviewNoNoYesParka750192144,000Coreloft60 g/m²90D 2L Gore-TexAround TownRegular1.1 kg / 2 lb 5.4 oz91 cm / 36 in
Patagonia Frozen Range (Men's - Women's)-6/-21ReviewNoNoNoParka700268187,600N/AN/A4 oz 75-denier polyesterAround TownRegular1.253 kg / 2 lb 12.2 oz84 cm / 33 in
Mountain Equipment Li. Ec. (Men's - Women's)-5/-20NoNoYesDown700295206,500N/AN/A50D DriliteAll RoundRegular822 g / 1 lb 13 oz72 cm / 28 in
Arc'teryx Patera Long (Women's)-2/-19NoNoYesParka7507455,500Coreloft60 + 80 g/m²2L Gore-TexAround TownRegular1.1 kg / 2 lb 6.8 oz117.5 cm / 46.25 in
Rab Neutrino Pro (Men's - Women's)-2/-19NoYesYesDown800212169,600N/AN/A20D Pertex Quantum ProAll RoundRegular585 g / 1 lb 8.6 oz77 cm / 30.3 in
Arc'teryx Dually Belay (Men's)0/-18ReviewNoYesYesSyntheticN/AN/AN/AThermaTek92 g/m²30D NylonAround TownRegular705 g / 1 lb 9 oz84 cm / 33 in
Arc'teryx Centrale (Women's)0/-18ReviewNoNoYesParka750157117,750Coreloft60 g/m²N90p NylonAround TownRegular885 g / 1 lb 15.2 oz95 cm / 37.5 in
Arc'teryx Camosun (Men's)0/-18ReviewNoNoNoParka75010578,750Coreloft140 g/m²N150p-X Gore-TexAround TownTrim960 g / 2 lb 1.9 oz80 cm / 31.5 in
Arc'teryx Cerium SV (Men's)0/-18ReviewNoYesNoDown850162137,700Coreloft80 + 140 g/m²Arato 7 & 10All RoundRegular415 g / 14.6 oz69.5 cm / 27.4 in
Arc'teryx Revet (Men's)2/-17NoNoYesParka750?N/AN/A20d nylon/spandex double weaveAround TownRegular755 g / 1 lb 10.6 oz91 cm / 36 in
Arc'teryx Piedmont (Men's)3/-16NoYesYesParka750218163,500N/AN/AArato 10Around TownRegular515 g / 1 lb 2.2 oz82 cm / 32.25 in
Arc'teryx Fission SV (Men's - Women's)3/-16ReviewNoNoYesSyntheticN/AN/AN/ACoreloft Continuous90 + 65 g/m²N80p-X Gore-Tex 2LAll RoundRegular890 g / 1 lb 15.4 oz81 cm / 31.8 in
Arc'teryx Alpha Lightweight (Men's)3/-16NoYesYesDown85011799,450Coreloft Compact40 g/m²Hadron 2L Gore-Tex InfiniumClimbingRegular540 g / 1 lb 3 oz?
Outdoor Research Sup. Alp. (Men's - Women's)3/-16NoNoYesDown800182145,600N/AN/A30D Pertex Quantum ProAll RoundRegular825 g / 1 lb 13.1 oz85 cm / 33.5 in
Arc'teryx Alessa Long (Women's)3/-16NoNoNoParkaN/AN/AN/ACoreloft80 + 120 g/m²N90p 2L Gore-TexAround TownRegular1.015 kg / 2 lb 3.8 oz123 cm / 48.5 in
Patagonia Tres 3-in-1 (Men's - Women's)3/-16ReviewNoNoNoParka70011882,600N/AN/A5.5 oz polyesterAround TownRegular1.307 kg / 2 lb 14.1 oz85 cm / 33.5 in
Arc'teryx Radsten Parka (Men's)3/-16NoNoNoParkaN/AN/AN/ACoreloft Compact120 g/m²NP100d Gore-Tex 2LAround TownRegular745 g / 1 lb 10.3 oz82 cm / 32.25 in
Rab Electron Pro (Men's - Women's)5/-15NoYesYesDown800180144,000N/AN/A20D Pertex Quantum ProAll RoundRegular525 g / 1 lb 2.5 oz74 cm / 29 in
Arc'teryx Therme Parka (Men's)5/-15ReviewNoNoYesParka75012090,000Coreloft60 + 80 g/m²P75d PolyesterAround TownRegular991 g / 2 lb 3 oz85 cm / 33.5 in
Arc'teryx Macai (Men's)5/-15ReviewYes, zipsNoNoDown7506951,750Coreloft Compact60 + 100 g/m²N40p-X 3L Gore-TexSki/SnowboardRegular1 kg / 2 lb 4 oz76 cm / 30 in
Arc'teryx Nuclei SV (Men's)5/-15ReviewNoYesYesSyntheticN/AN/AN/ACoreloft Continuous180 g/m2 + 90 g/m2Arato 15ClimbingRegular600 g / 1 lb 5.2 oz81 cm / 31.8 in
Patagonia DAS Parka (Men's)5/-15NoYesYesParkaN/AN/AN/APrimaLoft Gold Insulation Eco133 + 40 gPertex Quantum ProAround TownRegular555 g / 1lb 3.6 oz84 cm / 33 in
Arc'teryx Patera (Women's)5/-15ReviewNoNoYesParka7505843,500Coreloft60 + 80 g/m²2L Gore-TexAround TownTrim867 g / 1 lb 14.6 oz93 cm / 37 in
Black Diamond Access Down (Men's - Women's)7/-14NoYesYesDown700155108,500N/AN/A30D ripstop nylonAll RoundRegular442 g / 15.6 oz76 cm / 29.75 in
Arc'teryx Kappa (Men's)7/-14ReviewNoNoYesSyntheticN/AN/AN/ACoreloft Continuous140 g/m²N70p Gore ThermiumAll RoundRegular755 g / 1 lb 10.6 oz80 cm / 31.5 in
Arc'teryx Prema Down Coat (Women's)7/-14NoNoYesParka7509269,000N/AN/ANylonAround TownRegular794 g / 1 lb 12 oz117 cm / 46.1 in
Arc'teryx Radsten Insulated (Men's)7/-14NoNoNoParkaN/AN/AN/ACoreloft Compact120 g/m²NP100d Gore-Tex 2LAround TownRegular715 g / 1 lb 9.2 oz73 cm / 28.75 in
Rab Microlight Alpine (Men's - Women's)7/-14NoYesNoDown700153107,100N/AN/A30D Pertex QuantumAll RoundRegular466 g / 1 lb 0.5 oz72 cm / 28.5 in
Arc'teryx Thorium (Men's - Women's)7/-14ReviewNoYesYesDown750140105,000Coreloft80 + 140 g/m²Arato 30All RoundRegular517 g / 1 lb 2.2 oz71.5 cm / 28.1 in
Feathered Friends Eos8/-13NoYesNoDown90010594,500N/AN/APertex QuantumAll RoundRegular306 g / 10.8 oz?
Arc'teryx Thorium AR (Men's - Women's)8/-13ReviewNoYesNoDown75013097,500Coreloft80 + 140 g/m²Arato 30All RoundRegular490 g / 1 lb 1.3 oz72 cm / 28.3 in
Patagonia Macro Puff (Men's - Women's)8/-13ReviewNoNoNoSyntheticN/AN/AN/APlumaFill135 + 90 g10D Recycled nylon ripstopAll RoundRegular435 g / 15.3 oz79 cm / 31 in
Arc'teryx Macai LT (Men's)8/-13Yes, zipsNoNoDown7504936,750Coreloft Compact60 g/m²N40p-X 3L Gore-TexSki/SnowboardRegular855 g / 1 lb 14.2 oz74 cm / 29.1 in
Arc'teryx Seyla (Women's)8/-13NoNoYesParka7509269,000N/AN/AArato 10Around TownRegular507 g / 1 lb. 1.9 oz.87 cm / 34.4 in
Patagonia Fitz Roy (Men's - Women's)8/-13NoYesNoDown800128102,400N/AN/A20D NylonAll RoundRegular632 g / 1lb 6.3 oz74 cm / 29 in
Arc'teryx Koda (Men's)8/-13NoNoNoParkaN/AN/AN/ACoreloft80 + 140 g/m²N80p-X Gore-TexAround TownRegular720 g / 1 lb 9.4 oz75 cm / 29.5 in
Patagonia Vosque 3-in-1 (Women's)10/-12ReviewNoNoNoParkaN/AN/AN/AThermoLite100 g65% nylon, 35% polyesterAround TownRegular1.360 kg / 3 lb90 cm / 35.5 in
Patagonia City Storm Down (Men's - Women's)12/-11NoYesNoParka700191133,700N/AN/A4.2 oz polyesterAll RoundRegular468 g / 16.5 oz91 cm / 36 in
Patagonia Jackson Glacier (Men's - Women's)12/-11ReviewNoNoYesParka70014198,700N/AN/A3.6 oz 50D polyesterAround TownRegular880 g / 1 lb 15 oz79 cm / 31 in
Arc'teryx Sensa (Women's)14/-10NoNoYesParkaN/AN/AN/ACoreloft Compact120 g/m²NP100d Gore-Tex 2LAround TownRelaxed785 g / 1 lb 11.7 oz86 cm / 34 in
Patagonia Hi Loft Down (Men's - Women's)14/-10ReviewNoYesNoDown600177106,200N/AN/A1.4 oz 30D polyesterAll RoundRegular540 g / 1 lb 3 oz76 cm / 30 in
REI Magma 850 Hoodie 2.0 (Men's - Women's)14/-10NoYesNoDown850120102,000N/AN/APertex mini ripstop nylonAll RoundRegular340 g / 13.75 oz74 cm / 29.25 in
Arc'teryx Beta Insulated Coat (Women's)16/-9ReviewNoNoYesSyntheticN/AN/AN/ACoreloft 80 g/m² + 120 g/m²2L 40D Gore-TexAround TownRegular600 g / 1 lb 5.2 oz?
Arc'teryx Atom AR (Men's - Women's)18/-8ReviewYes, meshNoNoSyntheticN/AN/AN/ACoreloft Continuous120 g/m2 + 80 g/m2 + 60 g/m230D TyonoAll RoundRegular475 g / 1 lb 74 cm / 29.1 in
Patagonia Downdrift (Men's - Women's)18/-8NoNoNoDown600279167,400N/AN/A4.2 oz polyesterAround TownRegular1.014 kg / 2 lb 3.8 oz?
Arc'teryx Magnus (Men's)19/-7NoNoNoParkaN/AN/AN/ACoreloft80 gN60p Gore-Tex 2LAround TownRegular690 g / 1 lb 8.3 oz83 cm / 32.5 in
Arc'teryx Agrium (Men's - Women's)21/-6NoYesNoDown85011799,450N/AN/AAratoAll RoundRegular365 g / 12.9 oz75 cm / 29.5 in
Patagonia AlpLight Down (Men's - Women's)21/-6NoYesNoDown80010080,000N/AN/A0.8 oz 10D polyesterAll RoundSlim270 g / 9.5 oz74 cm / 29 in
Arc'teryx Beta Insulated (Men's - Women's)21/-6ReviewYes, zipsNoYesSyntheticN/AN/AN/ACoreloft Continuous80 g/m²2L 40D Gore-TexAll RoundRegular680 g / 1 lb 8 oz78.5 cm / 31 in
Patagonia Topley (Men's)23/-5NoNoYesDown700172120,400N/AN/A6 oz polyesterAll RoundRegular1.133 kg / 2 lb 8 oz77 cm / 30.5 in
Arc'teryx Alpha IS (Men's)23/-5NoYesYesSyntheticN/AN/AN/ACoreloft Continuous65 g/m²N40p-X 2L Gore-TexClimbingRegular610 g / 1 lb 5.5 oz78 cm / 30.75 in
Rab Xenon 2.0 (Men's - Women's)23/-5NoYesYesSyntheticN/AN/AN/APrimaLoft Silver60 g30D Pertex QuantumAll RoundRegular385 g / 13.6 oz71.5 cm / 28.1 in
Patagonia Down Sweater (Men's - Women's)23/-5ReviewNoYesNoDown800150120,000N/AN/A1.4 oz 20x30D polyesterAll RoundRegular428 g / 15.1 oz67 cm / 26.25 in
Arc'teryx Ralle Parka (Men's)25/-4NoNoYesParkaN/AN/AN/ACoreloft 80 g/m²2L 40D Gore-TexAround TownRegular735 g / 1 lb 9.9 oz?
Patagonia Silent Down (Men's - Women's)26/-3ReviewNoNoNoDown70010976,300N/AN/A2.2 oz polyesterAround TownRegular585 g / 1 lb 4.7 oz74 cm / 29 in
Arc'teryx Therme Insulated (Men's)26/-3ReviewNoNoNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²2L Gore-TexAround TownRegular960 g / 2 lb 1.9 oz73 cm / 28.75 in
Arc'teryx Cerium (Men's - Women's)26/-3NoYesNoDown85011396,050Coreloft 80 + 100 g/m²Arato 15All RoundTrim335 g / 11.8 oz?
Mountain Hardwear GW/2 (Men's - Women's)28/-2NoYesNoDown8008568,000N/AN/A10D Ripstop NylonAll RoundTrim250 g / 8.8 oz70 cm / 27.5 in
Arc'teryx Cerium LT (Men's - Women's)28/-2ReviewNoYesNoDown85010286,700Coreloft 80 + 100 g/m²Arato 10All RoundTrim305 g / 10.8 oz72 cm / 28.3 in
Arc'teryx Nuclei FL (Men's - Women's)32/0ReviewNoYesNoSyntheticN/AN/AN/ACoreloft Continuous65 g/m²Arato 10rClimbingTrim325 g / 11.5 oz75 cm / 29.5 in
Patagonia DAS Light (Men's - Women's)34/1NoYesYesSyntheticN/AN/AN/APlumaFill65 g0.8-oz 10-denier Pertex Quantum ProClimbingRegular320 g / 11.3 oz77 cm / 30.5 in
Patagonia Micro Puff (Men's - Women's)36/2ReviewNoYesNoSyntheticN/AN/AN/APlumaFill65 gPertex QuantumAll RoundTrim298 g / 10.5 oz75 cm / 29.5 in
Patagonia Isthmus (Men's)36/2NoNoNoParkaN/AN/AN/AThermoGreen60 g4.2 oz polyesterAround TownRegular895 g / 1 lb 15.6 oz70 cm / 27.5 in
Arc'teryx Proton LT (Men's - Women's)37/3ReviewNoNoNoSyntheticN/AN/AN/ACoreloft Compact80 g/m2 + 60 g/m2Fortius Air 20ClimbingTrim375 g / 13.2 oz75 cm / 29.4 in
Patagonia Nano Puff (Men's - Women's)37/3ReviewNoYesNoSyntheticN/AN/AN/APrimaLoft Gold Insulation Eco60 g22D PolyesterAll RoundRegular363 g / 12.8 oz71.5 cm / 28 in
Arc'teryx Norvan SL Ins. (Men's - Women's)39/4NoYesNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²Gore-Tex ShakeDryRunningTrim270 g / 9.5 oz71.5 cm / 28.1 in
Patagonia Nano Air (Men's - Women's)41/5ReviewNoNoNoSyntheticN/AN/AN/AFullRange60 g33D Nylon ripstopAll RoundTrim318 g / 11.2 oz?
Arc'teryx Atom LT (Men's - Women's)43/6ReviewYes, meshNoNoSyntheticN/AN/AN/ACoreloft Continuous60 g/m²20D TyonoAll RoundTrim375 g / 13.2 oz74 cm / 29.1 in
Arc'teryx Cerium SL (Men's - Women's)43/6ReviewNoYesNoDown8505849,300Coreloft 40 + 100 g/m²Arato 7All RoundTrim215 g / 7.6 oz69 cm / 27.2 in
Arc'teryx Proton Hybrid (Men's - Women's)46/8ReviewNoNoNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²Fortius™ Air 50All RoundTrim365 g / 12.9 oz?
Arc'teryx Proton FL (Men's)48/9ReviewNoNoNoSyntheticN/AN/AN/AOcta Loft94 g/m²Fortius Air 20ClimbingTrim323 g / 11.4 oz77 cm / 30.4 in
Arc'teryx Atom SL (Men's - Women's)52/11ReviewYes, meshNoNoSyntheticN/AN/AN/ACoreloft Compact40 g/m²20D TyonoAll RoundTrim245 g / 8.6 oz72 cm / 28.3 in
REI Stormhenge Hybrid (Men's - Women's)TestingYes, zipsNoNoDown850?N/AN/A40D + 80DAll RoundRegular900 g / 1 lb 15.75 oz80 cm / 31.5 in
Arc'teryx Monitor Insulated (Women's)TestingNoNoYesParkaN/AN/AN/ACoreloft80 + 100 g/m²40D 3L Gore-TexAround TownOversized645 g / 1 lb 6.8 oz93 cm / 37 in
Arc'teryx Coelle (Women's)TestingNoNoYesParkaN/AN/AN/ACoreloft80 + 140 g/m²40D 2L Gore-TexAround TownRegular460 g / 1 lb 0.2 oz93 cm / 37 in

View full table at https://outdoorcrunch.com/best-arcteryx-jacket/. 

If you're confused now and don't know which jacket best corresponds to your own needs, then follow the advice given in https://arcteryx.com/us/en/shop/jacket-finder/. 

The temperature ratings in this list are intended to represent the lowest temperatures you can wear each jacket without feeling uncomfortably cold. 

Keep in mind that these are only approximate values, assuming: 

  • worn over a shirt only and no shell over, 
  • during daily use (strolls, power walks etc at most - no high output activities), 
  • with light wind, 
  • and when it's dry out.

These values applicable to your torso only. Your hands, legs and feet are still subject to their own additional insulation.

The best practice is usually to use this table for comparing each jacket to one another, rather than pinpointing their ratings. 

Also, ratings will best respond to males. As most women tend to run colder than men, for women, shifting these ratings a bit is recommended. 

Always opt for the warmer option when in doubt. For jackets with Atom AR level warmth and beyond, recommended is almost always the hooded models. 

  • Also see: Arc'teryx Shells
NameBottom lineActivityReviewBreathabilityWeather Res.DurabilityPackabilityTemp (F/C)Pit zips?Two way zipper?Stuffs into itself?Hood?Face FabricFitWeightLengthMeasurements
Alpha FL (Men's - Women's)Climbing4/105/106/1010/10N/ANoNoYesStormHoodHadron 3L Gore-TexTrim209 g / 7.4 oz76.5 cm / 30 in[Men's / Women's]
Alpha SL (Men's - Women's)Climbing3/104/106/109/10N/ANoNoYesStormHoodN40p 3L Gore-TexTrim326 g / 11.5 oz77.5 cm / 30.5 in[Men's / Women's]
Alpha AR (Men's - Women's)Go-to climbing harshell. ClimbingReview8/107/108/104/10N/AYesNoNoStormHoodN40d & N80d Most Rugged 3L Gore-Tex ProRegular430 g / 15.2 oz79.5 cm / 31.25 in[Men's]
Alpha SV (Men's - Women's)Strongest climbing hardshell. ClimbingReview8/1010/1010/103/10N/AYesNoNoStormHoodN100d Most Rugged 3L Gore-Tex ProRegular510 g / 1 lb 2 oz78 cm / 30.75 in[Men's]
Alpha IS (Men's)Climbing7/105/105/108/1023/-5NoYesYesStormHoodN40p-X 2L Gore-TexRegular610 g / 1 lb 5.5 oz78 cm / 30.75 in
Beta (Men's - Women's)All Round5/105/104/105/10N/ANoNoNoStormHoodN30p-X 3L Gore-TexFitted300 g / 10.6 oz76 cm / 30 in
Beta Long (Men's)All RoundReview5/108/108/103/10N/ANoNoNoStormHoodN80p 3L Gore-TexRegular441 g / 15.6 oz85 cm / 33.5 in
Beta Coat (Women's)All Round7/105/104/105/10N/ANoYesNoStormHood3L Gore-TexRegular320 g / 11.3 oz?[Men's / Women's]
Beta LT Hadron (Men's - Women's)All Round5/105/104/105/10N/ANoNoNoStormHoodHadron 3L Gore-TexFitted255g / 9 oz76 cm / 30 in
Beta LT (Men's - Women's)Beta AR alternative. All RoundReview8/107/108/105/10N/AYesNoNoStormHoodN40d 3L Gore-TexFitted395 g / 13.9 oz76 cm / 30 in
Beta Insulated (Men's - Women's)Best insulated shell. All Round10/104/104/102/1021/-6YesYesNoStormHoodN40d 2L Gore-TexRegular680 g / 1 lb 8 oz78.5 cm / 31 in[Men's / Women's]
Beta Insulated Coat (Women's)Beta Insulated alternative. All Round7/104/104/102/1016/-9NoYesNoStormHoodN40d 2L Gore-TexRegular600 g / 1 lb 5.2 oz?[Men's / Women's]
Beta AR (Men's - Women's)Go-to all-round harshell. All RoundReview8/108/108/104/10N/AYesNoNoDropHoodN40r-X & N80p-X Most Rugged 3L Gore-Tex ProRegular460 g / 1 lb 76 cm / 30 in
Beta SV (Men's - Women's)Strongest all-round harshell. All RoundReview8/1010/109/103/10N/AYesNoNoStormHoodN80p-X Most Rugged 3L Gore-Tex ProRegular495 g / 1 lb 1.5 oz79 cm / 31 in[Men's / Women's]
Alpine Guide (Men's - Women's)All Round8/1010/109/103/10N/AYesNoNoStormHoodN80d-X Most Rugged 3L Gore-Tex ProRegular480g / 1 lb 0.9 oz?[Men's]
Gamma SL (Men's - Women's)A trimmer Gamma LT. All RoundReview7/102/106/105/10N/ANoNoNoStormHoodFortius 1.0Trim310 g / 10.9 oz74 cm / 29.1 in[Men's / Women's]
Gamma LT (Men's)A fleeceless, trimmer Gamma MX. All RoundReview7/103/107/103/10N/ANoNoNoStormHoodWee BurlyRegular545 g / 1 lb 3.2 oz76 cm / 30 in[Men's / Women's]
Gamma MX (Men's - Women's)A softshell with a fleece. All RoundReview6/104/108/103/10N/ANoNoNoStormHoodFortius 2.0Regular555 g / 1 lb 3.6 oz74 cm / 29.1 in[Men's / Women's]
Rush (Men's - Women's)Go-to ski jacket. SkiingReview8/109/109/103/10N/AYesNoNoStormHoodN80p-X & N100p-X 3L Most Rugged Gore-Tex ProRegular590 g / 1 lb 4.8 oz79.5 cm / 31.25 in[Men's]
Sabre (Men's)Alternative to Rush. Skiing8/108/108/102/10N/AYesNoNoStormHoodN80p-X 3L Gore-TexRegular705 g / 1 lb 8.9 oz79 cm / 31 in
Sentinel (Women's)Skiing8/108/108/102/10N/AYesNoNoStormHoodN70p 3L Gore-TexRegular370 g / 13.1 oz?
Macai (Men's)Go-to insulated ski jacket. SkiingReview10/108/109/101/105/-15YesNoNoDropHoodN40p-X 3L Gore-TexRegular1 kg / 2 lb 3.3 oz75 cm / 29.5 in
Macai LT (Men's)A lighter Macai with StormHood. Skiing8/107/108/101/108/-13YesNoNoStormHoodN40p-X 3L Gore-TexRegular855 g / 1 lb 14.2 oz?[Men's]
Andessa (Women's)Go-to insulated ski jacket. Skiing10/10TestingTesting1/108/-13YesNoNoDropHoodN40d 3L Gore-TexTrim869 g / 1 lb 14.7 oz?
Andessa Shell (Women's)Non-insulated Andessa. Skiing5/10TestingTesting3/10N/ANoNoNoDropHoodN70p 3L Gore-TexTrim560 g / 1 lb 3.8 oz?
Theriss Down (Women's)Skiing8/106/107/102/10TestingYesNoNoStormHoodN80p 2L Gore-TexRegular709 g / 1 lb 9 oz?
Rush IS (Women's)An insulated Rush. Skiing5/10TestingTesting9/1016/-9NoNoYesStormHoodGore-Tex InfiniumRegular515 g / 1 lb 2.2 oz?
Sentinel IS (Women's)SkiingTestingTestingTestingTesting21/-6YesNoNoStormHoodN80p 2L Gore-TexRegular600 g / 1 lb 5.2 oz?[Women's]
Ski Guide (Men's - Women's)SkiingTestingTestingTestingTestingN/AYesNoNoDropHoodN80d Most Rugged 3L Gore-Tex ProRegular570 g / 1 lb 4.1 oz?
Micon HeatherSkiingTestingTestingTestingTestingN/AYesNoNoStormHoodNP100-d 3L Gore-TexRegular685 g / 1 lb 8.2 oz83 cm / 32.5 in[Men's]
Micon (Men's)SkiingTestingTestingTestingTestingN/AYesNoNoStormHoodN80p 3L Gore-TexRegular685 g / 1 lb 8.2 oz83 cm / 32.5 in[Men's]
Cassiar (Men's)SkiingReview8/107/108/103/10N/AYesNoNoDropHoodN70p 3L Gore-TexTrim820 g / 1 lb 12.9 oz74.5 cm / 29.3 in[Women's]
Cassiar LT (Men's)SkiingReview6/106/106/105/10N/AYesNoNoDropHoodN70p 3L Gore-TexTrim605 g / 1 lb 5.3 oz75 cm / 29.5 in[Women's]
Ravenna (Women's)SkiingReview8/107/108/103/10N/AYesNoNoDropHoodN70s-4 3L Gore-TexTrim725 g / 1 lb 9.6 oz69.5 cm / 27.4 in[Men's]
Ravenna LT (Women's)SkiingReview6/106/106/105/10N/AYesNoNoDropHoodN70p 3L Gore-TexTrim540 g / 1 lb 3 oz69 cm / 27.2 in[Men's]
Procline (Men's)SkiingTestingTestingTestingTestingN/AYesNoNoStormHoodN70p Gore-Tex InfiniumTrim720 g / 1 lb 9.4 oz76 cm / 30 in[Women's]
Shashka Stretch (Women's)SkiingTestingTestingTestingTestingN/AYesNoNoStormHoodN70p Gore-Tex InfiniumTrim670 g / 1 lb 7.6 oz71 cm / 28 in[Women's]
Sabre AR (Men's)SkiingReview7/108/107/107/10N/AYesNoNoStormHoodN70p 3L Gore-TexRegular700 g / 1 lb 8.7 oz79 cm / 31 in[Men's]
Sentinel AR (Women's)SkiingReview7/108/107/107/10N/AYesNoNoStormHoodN70p 3L Gore-TexRegular590 g / 1 lb 4.8 oz72.5 cm / 28.5 in[Women's]
Sabre LT (Men's)SkiingReview7/108/107/108/10N/AYesNoNoStormHoodN80p 3L Gore-TexRegular660 g / 1 lb 7.3 oz83 cm / 32.5 in
Sentinel LT (Women's)SkiingReview7/108/107/108/10N/AYesNoNoStormHoodN80p 3L Gore-TexRegular565 g / 1 lb 3.9 oz73.5 cm / 29 in
Incendia (Women's)SkiingReview8/109/109/103/10N/AYesNoNoStormHoodNP100d 3L Gore-TexTrim610 g / 1 lb 5.5 oz79 cm / 31 in[Women's]
Indencia ISSkiingTestingTestingTestingTestingTestingYesNoNoStormHoodN80p 2L Gore-TexRegular?78 cm / 30.75 in[Men's / Women's]
Norvan LT (Men's - Women's)Go-to running jacket. Running5/105/108/106/10N/ANoNoNoStandardN13p 3L Gore-TexFitted190 g / 6.7 oz?[Women's]
Squamish (Men's - Women's)Trimmer, lighter, packable running jacket. RunningReview5/104/107/109/10N/ANoNoYesStormHood30D TyonoTrim140 g / 4.9 oz77.5 cm / 30.5 in[Women's]
Norvan SL Ins. (Women's)RunningTestingTestingTestingTesting39/4NoNoYesStandardGore-Tex ShakeDryTrim270 g / 9.5 oz71.5 cm / 28.1 in[Women's]
Cita (Women's)RunningReview7/104/105/1010/10N/ANoNoYesStandardLuminTrim120 g / 4.2 oz67.5 cm / 26.5 in[Men's]
Cita SL (Women's)RunningReview7/104/104/1010/10N/AYesNoYesStandardPermeair 20Trim65 g / 2.3 oz61.5 cm / 24.2 in[Men's]
Incendo (Men's)RunningReview7/104/105/1010/10N/ANoNoYesStandardLuminTrim125 g / 4.4 oz?
Incendo SL (Men's)RunningReview7/104/104/1010/10N/ANoNoYesStandardPermair 20 & CanimTrim80 g / 2.8 oz73 cm / 28.75 in[Men's / Women's]
Incendo AirshellRunningTestingTestingTestingTestingN/ANoNoYesStandard????[Men's]
Norvan SL (Men's - Women's)RunningReview7/106/108/108/10N/ANoNoYesStandardGore-Tex InfiniumTrim120 g / 4.2 oz77 cm / 30.4 in[Women's]
Trino SL (Men's)RunningReview8/105/107/106/10N/ANoNoNoStandardGore-Tex InfiniumTrim340 g / 12 oz74 cm / 29.1 in[Men's / Women's]
Trino SL Anorak (Women's)RunningReview8/107/108/107/10N/ANoNoNoStandardGore-Tex InfiniumTrim290 g / 10.2 oz65 cm / 25.5 in[Men's / Women's]
Nodin (Men's - Women's)Running8/105/105/1010/10N/ANoNoYesStandard20D TyonoTrim155 g / 5.5 oz75 cm / 29.5 in[Men's / Women's]
Solano (Men's - Women's)Around TownReviewTestingTestingTestingTestingN/ANoNoNoStandardGore-Tex InfiniumRelaxed355 g / 12.5 oz72 cm / 28.3 in
Venda Anorak (Women's)Around TownTestingTestingTestingTestingN/ANoNoNoStandardGore-TexRelaxed255 g / 9 oz75.5 cm / 29.7 in
Zeta FL (Men's - Women's)Hiking4/106/104/106/10N/ANoNoNoStormHoodN20r 2L Gore-TexTrim221 g / 7.8 oz76 cm / 30 in[Men's / Women's]
Zeta SL (Men's - Women's)HikingReview3/105/104/105/10N/ANoNoNoStormHood2L Gore-TexTrim310 g / 10.9 oz77.8 cm / 30.6 in[Men's]
Zeta LT (Men's - Women's)Hiking5/107/108/105/10N/ANoNoNoStormHoodN40P-X 3L Gore-TexTrim335 g / 11.8 oz78 cm / 30.75 in[Men's]
Zeta AR (Men's)Hiking7/108/107/104/10N/AYesNoNoStormHood3L Gore-TexRegular425 g / 15 oz80 cm / 31.5 in

Breathability

Going from top to bottom (Atom SL, LT and AR respectively), the warmth increases and the breathability decreases. 

Although Atom SL is the most breathable unit in the Atom line, Proton FL still breathes more.

Actually, as I explained before, this is also the case between Proton LT and Atom LT as well. 

Water, wind and abrasion resistances

While neither are comparable to outer layers (shell or belay jackets) at all, they'll fill the bill for spring and summer activities. 

They're comparable in terms of water resistances, but Atom SL (Tyono 20) offers a slightly more wind resistance and slightly less abrasion resistance compared to Proton FL (Fortius Air 20). 

They're both DWR coated. 

  • What is DWR by the way?

DWR is a coating. 

It's basically sprayed on to the surface of these jackets as a finish. It stands for Durable Water Repellent - which means that water will be repelled under wet conditions instead of soaking into the fabric. 

DWR also decreases dry time. 

It's a good thing these jackets are coated in DWR, but pay attention to the fact that DWR is a coating - meaning that it will wear off over time. 

Which is why you might want to invest in a DWR spray such as this one for after treatment. 

As you see, there's a strong correlation between FP x FW and temperature ratings, but not more than, say, 80%. I explained why this happens here in this post of mine. 

Fit and size measurements

For a small size Atom SL:

  • Chest width: 107 cm
  • Shoulder length: 16.4 cm
  • Waist width: 98.4 cm
  • Front length: 67.3 cm
  • Center back length: 71 cm

For a small size Proton FL: 

  • Chest width: 109 cm
  • Shoulder length: 14.8 cm
  • Waist width: 101.0 cm
  • Front length: 75.7 cm
  • Center back length: 75.7 cm

Both offer a trim cut. 

Conclusion

I'd probably get the Proton FL. It's more versatile. 

A helpful video review: 


I hope this post was helpful for you to learn more about the jacket(s) in your mind.


Feel free to ask me any questions or provide feedback and I'll be happy to respond in the comment section below.


Guide: Insulated & Shell Jackets

Start here:

  • Best Arc'teryx Jackets: My Top Picks
  • Best Patagonia Jackets: My Top Picks
  • Best Down Jackets: My Top Picks
  • Best Synthetic Insulated Jackets: My Top Picks
  • Temperature Ratings of Best Insulated Jackets
  • Arc'teryx Wiki: Complete Data Set
  • CLO values: Explained, compared & plotted
  • Ultimate Size Guide to Arc'teryx
  • StormHood vs DropHood

Complete list:

  • All Arc'teryx Shell Jackets sorted by performance
  • All Arc'teryx Ski Jackets sorted by performance
  • All Patagonia Ski Jackets sorted by performance
  • All Patagonia Winter Jackets compared
  • All Patagonia Fleeces compared
  • All Patagonia Rain Jackets compared
  • All Patagonia Down Jackets compared

Synthetic Insulated Jackets

  • Arc'teryx Proton LT
  • Patagonia Nano Air
  • Arc'teryx Atom LT
  • Arc'teryx Atom AR
  • Patagonia Nano Puff
  • Patagonia Micro Puff
  • Arc'teryx Atom SL
  • Arc'teryx Proton FL
  • Arc'teryx Proton Hybrid Hoody
  • Arc'teryx Fission SV
  • Arc'teryx Dually Belay Parka
  • Arc'teryx Atom SL Anorak
  • Arc'teryx Kappa

Down Jackets

  • Arc'teryx Cerium LT
  • Arc'teryx Cerium SV
  • Arc'teryx Cerium SL
  • Arc'teryx Thorium AR
  • Patagonia Down Sweater
  • Arc'teryx Firebee AR
  • Arc'teryx Ceres SV

Parkas

  • Arc'teryx Thorsen
  • Arc'teryx Therme
  • Arc'teryx Camosun
  • Arc'teryx Patera
  • Arc'teryx Centrale
  • Patagonia Tres
  • Patagonia Vosque

Shell Jackets

  • Arc'teryx Beta SV
  • Arc'teryx Beta FL
  • Arc'teryx Beta AR
  • Arc'teryx Alpha AR
  • Arc'teryx Alpha SV
  • Arc'teryx Gamma MX
  • Arc'teryx Gamma LT
  • Arc'teryx Gamma SL

Ski Jackets

  • Arc'teryx Rush
  • Arc'teryx Rush IS
  • Arc'teryx Sabre LT
  • Arc'teryx Sabre AR
  • Arc'teryx Cassiar
  • Arc'teryx Sidewinder
  • Arc'teryx Macai

Fleece Jackets

  • Patagonia R1
  • Patagonia R2
  • Patagonia Synchilla
  • Patagonia Better Sweater

Wind Jackets

  • Arc'teryx Solano
  • Arc'teryx Nuclei FL
  • Patagonia Houdini
  • Patagonia Houdini Air
  • Arc'teryx Squamish
  • Arc'teryx Incendo
  • Arc'teryx Norvan SL
  • Arc'teryx Trino SL

Rain Jackets

  • Patagonia Torrentshell
  • Patagonia Torrentshell Insulated
  • Arc'teryx Beta SL Hybrid
  • Arc'teryx Zeta FL

Also see:

  • Arc'teryx vs Patagonia
  • List of Manufacturing Facilities of all Arc'teryx Jackets

Thank you for reading!

Filed Under: Synthetic Insulated Jackets Tagged With: Arc’teryx Atom SL, Arc’teryx Proton FL, arcteryx, arcteryx insulated jackets, arcteryx jackets, jackets

Reader Interactions

Comments

  1. Julie says

    February 15, 2021 at 1:48 am

    Hello,
    What ti wear over the proton fl in winter to protect from wind and little more heat?

  2. mike says

    April 12, 2021 at 1:45 am

    here is my current setup for winter ice climbing;

    Base Layer : OR echo t-shirt (Synthetic moisture wicking tee shirt)
    Mid/insultation layer : Patagonia R1 fleece
    Shell : Arcteryx Alpha FL

    This setup works great when combine it all together when climbing, but i often overheat on the approach. If i take the shell off the wind cuts right through the R1. I am hesitating between the Proton FL and the new atom sl anork. Any suggestion?

  3. Randy says

    December 16, 2021 at 9:25 am

    Thanks for the review. I have one Proton FL and am trying to purchase another. They seem to have disappeared or are no longer in stock. Supply problems or has this great model been discontinued by Arcteryx? This jacket is my go-to mid-layer when it’s too warm (or I’m too warm) for my Atom LT, Proton LT, etc. Fantastic Arcteryx product. I have learned a lot (and purchased a lot) after reading reviews and comparisons on your website. Really appreciate your analysis!

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Hey, what's up? Canberk here. I try to approach outdoor gear from a scientific point of view. Here's more about me.

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