Arcteryx Phase AR Zip Neck - Men's synthetic PHASE AR ZIP NECK LS - Designed for high output in cooler temperatures, the Phase AR Zip Neck is a mens midweight baselayer top made from next generation Phasic AR. Engineered to provide insulation and offer performance stretch, Phasic AR uses different polyester yarn structures on its interior and face to rapidly wick and disperse moisture. The tall collar adds warmth, and the deep front zip provides ventilation. LIGHTWEIGHT - Lighter weight Phasic SL panels improve thermal regulation. Updated style lines and improved fit. PHASE - Quick dry base layer with excellent moisture management. For high output activities. ARC'TERYX ESSENTIALS - Versatile high performance designs for diverse activities and conditions. Durable and light.