Designed for high output in cooler temperatures, the Men\'s Phase AR Long Sleeve Zip Neck from Arc\'teryx is a midweight base layer top made from next generation Phasic AR fabric. It has been engineered to provide insulation and offer performance stretch, and 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 while the lighter weight Phasic SL panels improve thermal regulation.