From trailhead to summit, over bases or under a waterproof shell: this layer is made to mobilize. Only StretchDown(TM) is built with DoppleWeave(TM) stretch construction, so the fabric moves with you, and with Cohesion(TM) insulation interlock, so the down stays in place. This ultra-engineered construction and the highest quality down insulation combine warmth and movement for the full range of winter activities.Specs Uses: Rock Climbing, Hiking, Travel, Camping Fabric Body: DoppleWeave(TM) 20D: 85% Nylon, 15% Elastane Center Back Length: 28 in / 71.1 cm