The Proton LT is Arc'teryx's take on breathable insulation, a field currently dominated by Patagonia's Nano-Air series. Though not as warm as the Patagonia Nano-Air Hoody, we found the Proton just as breathable, and it feels much more durable. We've used and abused loads of jackets, living and working in them for months at a time as ski patrollers, climbing guides, and Search and Rescue team members, putting holes in Pertex fabric while we scraped up chimneys and offwidths. We've shredded the sleeves climbing flared granite hand cracks and 'shwacking through the brush in Joshua tree. When so many designs are getting lighter and more fragile, we're happy to see a tough jacket like the Proton LT.
Arc'teryx Proton LT Hoody Review
Cons: Warmth to weight ratio not as good as the Nano-Air
Compare to Similar Products
Our Analysis and Test Results
The Proton is best compared with the other breathable insulators in our review; the Patagonia Nano-Air Hoody, the Outdoor Research Ascendant Hoody, The North Face Summit L3 Ventrix Hoody, and the Patagonia Nano-Air Light Hybrid Hooded. Though not as breathable as some of these contenders, the Proton has a few unique features that set it apart from the rest of the pack.
The Proton uses Coreloft continuos 65 insulation and a shell fabric called Fortius Air 40, an air permeable variation on the fabric Arc'teryx uses on their Gamma MX softshell. This jacket is not as lofty or as warm as the Nano-Air Hoody, and the Nano-Air is softer. A few testers felt it makes a better mid layer, but we all appreciated the added durability that comes from a heavier fabric. The Proton feels warmer than the Nano-Air Light Hybrid Hoody, the OR Ascendant Hoody, and The North Face Ventrix Summit L3 Hybrid Hoody.
Weight & Compressibility
The small-sized Proton we tested weighs 13.7 ounces, a touch over an ounce heavier than the Nano-Air. Most of that weight comes from the thicker, more durable shell fabric. We don't recommend the Proton for folks who are long-distance hiking and counting every ounce, but for people who are tired of their ultralight puffys disintegrating at the crag, the Proton will be a welcome alternative. The Proton doesn't stuff into an internal pocket, which means you'll need a small stuff sack if you want to take it up a multi-pitch climb. We managed to stuff it down to about the size of a grapefruit and a half.
Though not as soft as the Nano-Air or the Outdoor Research Ascendant Hoody, but it possesses a number of unique features that add to its comfort level. The hood is large enough to easily fit over a climbing helmet, while a cinch cord ensures the hood will stay in place over your bare head, without obscuring your view. The cinch cord and cord locks on the hem are the best some of the best we've encountered. Not only are they low profile so you'd never notice them, but they are also oriented so that the slack from the tightened cord faces up, into the jacket. We've had carabiners snag on hem cords before, sometimes in some pretty desperate situations. One of our testers won't wear a jacket with a hem cinch. The Proton's design eliminates this issue. While the tough shell fabric isn't as supple as the Nano-Air's, we didn't feel like it was uncomfortable to wear in a sleeping bag. Thanks to a little stretch, it's easy to pull the sleeves up, and the Proton allows for a full range of motion.
This jacket is more wind resistant and repels water better than its older cousin, the Atom LT. We feel it has about the same water repelling abilities as the Patagonia Nano-Air Hoody, though the Nano-Air derives most of its water resistance from it's DWR treatment, which becomes less effective when the jacket gets dirty. The Proton, on the other hand, has a thicker, less absorbent shell fabric than the Nano-Air and a DWR treatment.
The Proton's air permeable shell puts it several notches above jackets constructed with Pertex fabric like the Rab Xenon X, but it isn't as breathable as the Patagonia Nano-Air Hoody. Again, the tradeoff is durability, and the Proton feels tougher than all of its competitors. Our testers feel that the Proton is even more breathable the Arc'teryx Atom LT, even though the Atom has thinner, stretchy side panels.
The shell fabric has a matte quality, and the Proton doesn't suffer from the shiny techy look of jackets made from lightweight Pertex fabrics. Our testers all feel that the Proton looks good around town, even better than the super popular Arc'teryx Atom LT. We also feel the durable shell fabric will keep this jacket from getting covered in patches anytime soon. Available in colors as light or as dark as you're feeling; Black, Pilot (gray), Rigel (blue), and Flare (red).
Any activity where you're moving more than you're standing around is the time for the Proton. Skinning or hiking up steep hills, Joshua Tree scambles, or cold weather cragging are all great applications for this robust, breathable jacket. It's sleek enough to be used as a mid-layer, but still warm and wind resistant to wear on its own if you're on the move.
$300 is expensive but on par with similar offerings from Patagonia. As we mentioned, the durability factor really distinguishes the Proton from the competition, and this makes it a great value in the eyes of our frugal testers who are tough on their gear.
With so many models out there trying to match the success of the Nano-Air, we're stoked to find that Arc'teryx's foray into the world of breathable insulated jackets is a unique offering with some advantages over the competition. The Proton is a smart choice for anyone who is tough on their gear and is willing to carry a few extra ounces for the sake of jacket longevity.
— Matt Bento