The Arc'teryx Men's Proton LT Jacket is an insulated jacket for lightweight warmth. When you're Climbing you generate your own body heat, but sometimes you just need a little extra to keep you toasty warm, all without overheating. Confusing yes, but a solution is here. The abrasion-resistant, 40D stretch woven exterior also resists wind and water, while still allowing air to permeate. Hidden within is Coreloft Continuous 65 Insulation, to give your body the midweight warmth it needs in the mountains. Stretchy cuffs you can push up your forearm as needed and 3 pockets with zippers to ensure your Items don't fall out. Features of the Arcteryx Men's Proton LT Jacket Fortius Air 40 outer fabric with DWR treatment layers easily and effectively balances air permeability with wind and water resistance Coreloft Continuous 65 Insulation in the body and arms Collar height provides coverage when worn without a hardshell External pockets: Two insulated hand pockets and single external chest pocket No Slip Zip works like a series of speed bumps keeping the main zipper from self-opening, Dual back flaps prevent wind penetration Dual hem adjustments seal in warmth Trim Fit for athletic Performance Articulated elbows and gusseted underarms Stretch-knit cuffs Chest pocket with zip Insulation: Lightweight and Highly compressible Advanced material Technologies balance wind, weather and thermal protection