The Men's Black Diamond Coefficient Vest was made to climbers looking for ultimate core insulation without the excess bulk and restriction of a full jacket. Lightweight, breathable, and highly stretchy the Coefficient vest is the perfect addition to your layering system for cool springs to frigid autumns. Made from Polartec PowerDry High Efficiency fleece the Coefficient vest keeps you warm while remaining super breathable and lightweight. Super stretchy fabric won't hinder your reach when stretching out for the next hand hold. A chamois-line collar keeps zipper chafe from irritating your chin when fully zipped. A zippered chest pocket is the perfect place to stash an energy gel or whatever else you'd like to keep close at hand. The Men's Black Diamond Coefficient Vest was made to allow for full freedom of movement while insulating your core when traveling over or climbing up rough alpine terrain.