New Arc’teryx Proton LT Claims 60x Durability in Light, Breathable Jacket

Arc’teryx remade the Proton LT Hoodie with climbing in mind. But the intelligently insulated layer may be the ultimate multitasker for any demanding outdoor activity in cooler temps.

Arc’teryx improved the Proton LT in every way. The revamped Proton LT Hoodie aims for high-output adventures.

“I have worn it hiking, biking, fishing, camping, climbing, and skiing,” said Arc’teryx Apparel Designer Brylee Geddis, one visionary behind the updated jacket. “It’s perfect for slightly colder temps when you’re working hard but still need the warmth and protection.”

“The lightweight Proton’s standout feature is its ability to breathe — and therefore stay on,” she continued.

“Not having to stop to shed layers on challenging pitch can be a lifesaver. With nonbreathable midlayers, you end up sweating on the approach or up-track, demanding you to de-layer. We hope this piece will remove the need for the sweat, freeze, on, off, stuff-it-in-your-bag situation.”

Her design team updated the Proton inside and out. “This isn’t our first go at breathable insulation,” Geddis said.

Arc’teryx introduced its first-generation Proton LT (lightweight) and AR (all-round) jackets in 2016. But the feedback was that the two pieces were too similar. So the team picked the more versatile 80g LT to push forward.

Arc’teryx Jacket Aims at Best-in-Class Durability, Air Permeability

The Arc’teryx Proton LT Hoodie is made of lightweight synthetic insulation known as Coreloft Compact 80. “By switching, we were able to reduce fiber migration while providing four-way stretch and great loft retention,” Geddis said.

That means this workhorse layer delivers solid base warmth, great airflow for sweaty endeavors, and an ultralight profile that doesn’t impede movement. The women’s small weighs 12.3 ounces; a men’s medium is just over 14 ounces.

Yet, remarkably, the ultralight Proton LT Hoodie is also hard-wearing, even in extreme conditions. To meet its future users’ dynamic moves and high output, the jacket needed an outer material to maintain structure and block the elements — all while in action.

So Arc’teryx engineered a new face fabric. The material technology, called Fortius Air 20, is a mix of 84 percent nylon and 16 percent elastane.

“Durability is key, especially for a climbing piece,” Geddis said. “Compared to other breathable insulated pieces out there, this is best-in-class for durability and air permeability.” In fact, in tests by the brand, the Proton LT proved 60 times more abrasion-resistant than the industry standard.

And we wondered how.

Proton LT Hoodie Wear and Field Tests

“We start with our material and validate it before we design,” Geddis said. Arc’teryx worked with both fabric vendors and an in-house development team to create 17 different wear tests, analyzing different material trials and combinations to achieve the right balance and durability.

Arc’teryx used the Martindale test to measure the Proton LT’s durability. Geddis explained, “This process simulates natural wear as the material is rubbed against a standard abrasive surface with a specific force. And at Arc’teryx, we do a modified test, which increases the textile failure.”

Simultaneously, they sent the fabric out in the field to see how it would wear naturally in its intended environments. “Ultimately, we were able to improve the comfort, air permeability, and stretch from the previous generation,” Geddis said.

Arc’teryx Proton LT: Design Details for Rock Climbers

Besides baked-in breathability and a tough face fabric for outdoor elements, the Proton LT comes with some thoughtful details that climbers and all active people can appreciate. Both in the hem and helmet-compatible hood, low-profile cord adjustment makes for simple cinching against the wind.

The pocket is Geddis’ favorite design element. “As a woman, I am super stoked to have a chest pocket on this jacket. It’s easily accessible while wearing a harness or backpack. I held four meetings with various women to nail down the right size and shape. It might be a small detail, but that pocket means a lot!” she exclaimed. 

Plus, in standard Arc’teryx fashion, the Proton LT Hoodie comes in some sleek, modern colors. These multiuse layers some in a few exclusive colors and retail for $299 at REI.

This article is sponsored by REI. Check out the Arc’teryx LT Hoodie, only at REI.