This article is moved to https://outdoorcrunch.com/arcteryx-proton-vs-atom/.
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). Like hauntingly dark yet brilliantly brilliant electronic music? Check out my Hidden Electronic Gems playlist at Spotify.
These jackets are more alike than they're different.
- Proton FL is a bit more durable, a bit more comfortable and is an inch longer
- Atom SL is a bit more breathable
Upvote your favorites. Quick links: Quick links:Poll results: Best colorways of Atom Series
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):
Performance data axis of synthetic jackets (table above) and shell jackets (this table) are different. Don't compare them.
Name Activity Breathability Weather Res. Durability Temp (F/C) Bottom line Review Pit zips? Two way zipper? Stuffs into itself? Hood? Face Fabric Fit Weight Length Alpha FL (Men's - Women's) Climbing 7/10 No data No data 10/10 N/A No No Yes Hadron 3L Gore-Tex Trim 209 g / 7.4 oz 76.5 cm / 30 in Yes Alpha SL (Men's - Women's) Climbing 5/10 7/10 No data 9/10 N/A No No Yes N40p 3L Gore-Tex Trim 326 g / 11.5 oz 77.5 cm / 30.5 in Yes Alpha (aka AR) (Men's - Women's) Climbing 8/10 9/10 8/10 4/10 N/A Go-to climbing harshell. Review Yes No No N40d & N80d Most Rugged 3L Gore-Tex Pro Regular 430 g / 15.2 oz 79.5 cm / 31.25 in No Alpha SV (Men's - Women's) Climbing 8/10 10/10 10/10 3/10 N/A Strongest climbing hardshell. Review Yes No No N100d Most Rugged 3L Gore-Tex Pro Regular 510 g / 1 lb 2 oz 78 cm / 30.75 in No Alpha IS (Men's) Climbing 7/10 5/10 No data 8/10 23/-5 No Yes Yes N40p-X 2L Gore-Tex Regular 610 g / 1 lb 5.5 oz 78 cm / 30.75 in Yes Beta (Men's - Women's) All Round 6/10 7/10 7/10 8/10 N/A Streamlined all-doer shell. Review No No No N30p-X 3L Gore-Tex Trim 300 g / 10.6 oz 76 cm / 30 in No Beta Lightweight (Men's - Women's) All Round 8/10 7/10 7/10 6/10 N/A Review Yes No No N40p 3L Gore-Tex Fitted 380 g / 13.4 oz 75 cm / 29.5 in No Beta LT (Men's - Women's) All Round 7/10 7/10 8/10 6/10 N/A Review Yes No No N40d 3L Gore-Tex Fitted 395 g / 13.9 oz 76 cm / 30 in No Beta AR (Men's - Women's) All Round 8/10 9/10 9/10 4/10 N/A Go-to all-round harshell. Review Yes No No N40d & N80d Most Rugged 3L Gore-Tex Pro Regular 460 g / 1 lb 76 cm / 30 in No Beta AR StormHood (Men's - Women's) All Round 8/10 9/10 9/10 4/10 N/A Review Yes No No N40d & N80d Most Rugged 3L Gore-Tex Pro Regular 460 g / 1 lb 76 cm / 30 in No Beta Coat (Women's) All Round 6/10 5/10 No data 5/10 N/A No Yes No 3L Gore-Tex Regular 320 g / 11.3 oz 88 cm / 34.5 in No Beta Insulated (Men's - Women's) All Round 9/10 7/10 8/10 No data 21/-6 Go-to hybrid jacket. Review Yes Yes No N40d 2L Gore-Tex Regular 680 g / 1 lb 8 oz 78.5 cm / 31 in No Beta Insulated Coat (Women's) All Round 7/10 No data No data No data 16/-9 No Yes No N40d 2L Gore-Tex Regular 600 g / 1 lb 5.2 oz 86 cm / 34 in No Beta Down Insulated (Men's) All Round 9/10 7/10 8/10 No data 0/-18 Yes Yes No 2L 40D Gore-Tex Regular 760 g / 1 lb 10.8 oz 79 cm / 31 in No Beta Long All Round 4/10 9/10 No data 3/10 N/A Review No No No N80p 3L Gore-Tex Regular 441 g / 15.6 oz 85 cm / 33.5 in Yes Beta LT Hadron All Round 7/10 6/10 4/10 5/10 N/A No No No Hadron 3L Gore-Tex Fitted 255 g / 9 oz 76 cm / 30 in Yes Beta SV (Men's - Women's) All Round 8/10 10/10 10/10 3/10 N/A Strongest all-round harshell. Review Yes No No N80p-X Most Rugged 3L Gore-Tex Pro Regular 495 g / 1 lb 1.5 oz 79 cm / 31 in Yes Gamma Lw. (aka SL) (Men's - Women's) All Round 7/10 2/10 6/10 5/10 N/A Review No No No Fortius 1.0 Trim 310 g / 10.9 oz 74 cm / 29.1 in No Gamma (aka LT) (Men's - Women's) All Round 7/10 3/10 7/10 3/10 N/A Go-to softshell. Review No No No Wee Burly Double Weave Regular 545 g / 1 lb 3.2 oz 76 cm / 30 in No Gamma MX (Men's - Women's) All Round 6/10 4/10 8/10 3/10 N/A Strongest softshell. Review No No No Fortius 2.0 Regular 555 g / 1 lb 3.6 oz 74 cm / 29.1 in No Sabre SV (Men's) Skiing 10/10 10/10 10/10 1/10 N/A Strongest ski jacket. Review Yes Yes No N100d Most Rugged 3L Gore-Tex Pro Regular 595 g / 1 lb 5 oz 85 cm / 33.5 in No Sabre (Men's) Skiing 8/10 8/10 7/10 2/10 N/A Review Yes No No N80p-X 3L Gore-Tex Regular 705 g / 1 lb 8.9 oz 79 cm / 31 in No Sabre Insulated (Men's) Skiing 7/10 No data 6/10 No data No data Review Yes No No N80p 2L Gore-Tex Regular 815 g / 1 lb 12.7 oz 76 cm / 30 in No Rush (Men's) Skiing 8/10 9/10 9/10 3/10 N/A Go-to ski jacket. Review Yes No No N80p-X & N100p-X 3L Most Rugged Gore-Tex Pro Regular 590 g / 1 lb 4.8 oz 79.5 cm / 31.25 in No Rush Insulated (Men's - Women's) Skiing 3/10 5/10 5/10 9/10 16/-9 Review No No Yes Hadron 2L Gore-Tex Infinium Regular 515 g / 1 lb 2.2 oz 79 cm / 31 in No Macai Shell (Men's) Skiing No data No data No data No data N/A Review Yes No No N80p-X 3L Gore-Tex Regular 775 g / 1 lb 11.3 oz ? No Macai (Men's) Skiing 7/10 7/10 6/10 1/10 5/-15 Review Yes No No N40p-X 3L Gore-Tex Regular 990 g / 2 lb 2.9 oz 75 cm / 29.5 in No Macai Lightweight (aka LT) (Men's) Skiing 7/10 7/10 6/10 2/10 8/-13 Review Yes No No N40p-X 3L Gore-Tex Regular 855 g / 1 lb 14.2 oz ? No Theriss Down (Women's) Skiing 7/10 6/10 7/10 2/10 No data Review Yes No No N80p 2L Gore-Tex Regular 709 g / 1 lb 9 oz 63 cm / 24.8 in No Sentinel (Women's) Skiing 8/10 7/10 7/10 2/10 N/A Go-to ski jacket. Review Yes No No N70p 3L Gore-Tex Regular 640 g / 1 lb 6.6 oz 73.7 cm / 29 in No Sentinel Insulated (Women's) Skiing 8/10 No data No data No data 21/-6 Review Yes No No N80p 2L Gore-Tex Regular 600 g / 1 lb 5.2 oz 79.8 cm / 31.5 in No Sentinel Relaxed (Women's) Skiing No data No data No data No data N/A Yes No No N80p 3L Gore-Tex Regular 655 g / 1 lb 7.1 oz ? No Sidewinder (Women's) Skiing 8/10 8/10 7/10 2/10 N/A Yes No No N80p 3L Gore-Tex Regular 570 g / 1 lb 4.1 oz ? No Andessa (Women's) Skiing 10/10 No data No data 1/10 8/-13 Yes No No N40d 3L Gore-Tex Trim 869 g / 1 lb 14.7 oz 67 cm / 26.4 in Yes Andessa Shell (Women's) Skiing 5/10 No data No data 3/10 N/A No No No N70p 3L Gore-Tex Trim 560 g / 1 lb 3.8 oz ? Yes Micon Heather Skiing No data No data No data No data N/A Yes No No NP100-d 3L Gore-Tex Regular 685 g / 1 lb 8.2 oz 83 cm / 32.5 in Yes Micon (Men's) Skiing No data No data No data No data N/A Yes No No N80p 3L Gore-Tex Regular 685 g / 1 lb 8.2 oz 83 cm / 32.5 in Yes Cassiar (Men's) Skiing 8/10 7/10 8/10 3/10 N/A Review Yes No No N70p 3L Gore-Tex Trim 820 g / 1 lb 12.9 oz 74.5 cm / 29.3 in Yes Cassiar LT (Men's) Skiing 6/10 6/10 6/10 5/10 N/A Review Yes No No N70p 3L Gore-Tex Trim 605 g / 1 lb 5.3 oz 75 cm / 29.5 in Yes Ravenna (Women's) Skiing 8/10 7/10 8/10 3/10 N/A Review Yes No No N70s-4 3L Gore-Tex Trim 725 g / 1 lb 9.6 oz 69.5 cm / 27.4 in Yes Ravenna LT (Women's) Skiing 6/10 6/10 6/10 5/10 N/A Review Yes No No N70p 3L Gore-Tex Trim 540 g / 1 lb 3 oz 69 cm / 27.2 in Yes Procline (Men's) Skiing No data No data No data No data N/A Yes No No N70p Gore-Tex Infinium Trim 720 g / 1 lb 9.4 oz 76 cm / 30 in Yes Shashka Stretch (Women's) Skiing No data No data No data No data N/A Yes No No N70p Gore-Tex Infinium Trim 670 g / 1 lb 7.6 oz 71 cm / 28 in Yes Sabre AR (Men's) Skiing 7/10 8/10 7/10 7/10 N/A Review Yes No No N70p 3L Gore-Tex Regular 700 g / 1 lb 8.7 oz 79 cm / 31 in Yes Sentinel AR (Women's) Skiing 7/10 8/10 7/10 7/10 N/A Review Yes No No N70p 3L Gore-Tex Regular 590 g / 1 lb 4.8 oz 72.5 cm / 28.5 in Yes Sabre LT (Men's) Skiing 7/10 8/10 7/10 8/10 N/A Review Yes No No N80p 3L Gore-Tex Regular 660 g / 1 lb 7.3 oz 83 cm / 32.5 in Yes Sentinel LT (Women's) Skiing 7/10 8/10 7/10 8/10 N/A Review Yes No No N80p 3L Gore-Tex Regular 565 g / 1 lb 3.9 oz 73.5 cm / 29 in Yes Incendia (Women's) Skiing 8/10 9/10 9/10 3/10 N/A Review Yes No No NP100d 3L Gore-Tex Trim 610 g / 1 lb 5.5 oz 79 cm / 31 in Yes Indencia IS Skiing No data No data No data No data No data Yes No No N80p 2L Gore-Tex Regular ? 78 cm / 30.75 in Yes Squamish (Men's - Women's) Running 5/10 4/10 7/10 9/10 N/A Go-to running jacket. Review No No Yes 30D Tyono Trim 140 g / 4.9 oz 77.5 cm / 30.5 in No Norvan Windshell (Men's - Women's) Running No data No data No data No data N/A No No Yes Permeair 20 Trim 90 g / 3.2 oz 73 cm / 28.75 in No Norvan Shell (Men's - Women's) Running No data No data No data No data N/A No No No 13D 3L Gore-Tex Trim 190 g / 6.7 oz 73 cm / 28.75 in No Nodin (Women's) Running 8/10 5/10 5/10 10/10 N/A No No Yes 20D Tyono Trim 130 g / 4.6 oz 75 cm / 29.5 in No Incendo Airshell (Women's) Running No data No data No data No data N/A No No Yes ? Trim 105 g / 3.7 oz ? No Incendo (Men's) Running 7/10 4/10 5/10 10/10 N/A Review No No Yes Lumin Trim 125 g / 4.4 oz ? Yes Norvan LT (Men's - Women's) Running 5/10 5/10 8/10 6/10 N/A No No No N13p 3L Gore-Tex Trim 190 g / 6.7 oz ? Yes Norvan SL Ins. (Women's) Running No data No data No data No data 39/4 No No Yes Gore-Tex ShakeDry Trim 270 g / 9.5 oz 71.5 cm / 28.1 in Yes Cita (Women's) Running 7/10 4/10 5/10 10/10 N/A Review No No Yes Lumin Trim 120 g / 4.2 oz 67.5 cm / 26.5 in Yes Cita SL (Women's) Running 7/10 4/10 4/10 10/10 N/A Review Yes No Yes Permeair 20 Trim 65 g / 2.3 oz 61.5 cm / 24.2 in Yes Incendo SL (Men's) Running 7/10 4/10 4/10 10/10 N/A Review No No Yes Permair 20 & Canim Trim 80 g / 2.8 oz 73 cm / 28.75 in Yes Norvan SL (Men's - Women's) Running 7/10 6/10 8/10 8/10 N/A Review No No Yes Gore-Tex Infinium Trim 120 g / 4.2 oz 77 cm / 30.4 in Yes Trino SL (Men's) Running 8/10 5/10 7/10 6/10 N/A Review No No No Gore-Tex Infinium Trim 340 g / 12 oz 74 cm / 29.1 in Yes Trino SL Anorak (Women's) Running 8/10 7/10 8/10 7/10 N/A Review No No No Gore-Tex Infinium Trim 290 g / 10.2 oz 65 cm / 25.5 in Yes Solano (Women's) Around Town No data No data No data No data N/A Review No No No Gore-Tex Infinium Relaxed 355 g / 12.5 oz 72 cm / 28.3 in No Venda Anorak (Women's) Around Town No data No data No data No data N/A No No No Gore-Tex Relaxed 255 g / 9 oz 75.5 cm / 29.7 in Yes Zeta FL (Men's - Women's) Hiking 4/10 6/10 4/10 6/10 N/A No No No N20r 2L Gore-Tex Trim 221 g / 7.8 oz 76 cm / 30 in Yes Zeta SL (Men's - Women's) Hiking 3/10 5/10 4/10 5/10 N/A Review No No No 2L Gore-Tex Trim 310 g / 10.9 oz 77.8 cm / 30.6 in Yes Zeta LT (Men's - Women's) Hiking 5/10 7/10 8/10 5/10 N/A No No No N40P-X 3L Gore-Tex Trim 335 g / 11.8 oz 78 cm / 30.75 in Yes Zeta AR (Men's) Hiking 7/10 8/10 7/10 4/10 N/A Yes No No 3L Gore-Tex Regular 425 g / 15 oz 80 cm / 31.5 in Yes
Breathability
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 and Atom 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 both DWR coated.
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 at arcteryx.com 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: