evo.com | Arc'teryx Synthetic Jackets > The Arc'teryx Proton SL Hoodie takes the guesswork out of warming up on cold climbs and other high-output activities in cool conditions. The knit insulation holds its loft and shape-no matter how often you stuff it into the bottom of your pack. More importantly, it allows your body to breathe, so you're not left a sweaty mess after you have to step on the gas to get through the crux. 100% Polyester Fitted Our trimmer fit is patterned to stay close to the body through the chest, waist, hip, and thigh. Its low profile eliminates bulk, moves with the body, and fits comfortably over first layers or under outer layers. Two Zippered Handwarmer Pockets Octa(R) Loft Fortius(TM) Air 20 88% Nylon / 12% Elastane | Women's Arc'teryx Proton SL Hoodie 2026 - Small Blue | Nylon/Elastane/Polyester