Arc'teryx Mens Phase AR Crew Long Sleeve Phasic AR Technology  100% Polyester Imported 3" high 6" wide PHASE AR CREW LS - A mens midweight baselayer top for high output in cooler temperatures, the Phase AR Crew is made from next generation Phasic AR. ENGINEERED FABRIC - An Arcteryx fabric engineered to provide insulation, dry quickly, and offer performance stretch, Phasic AR uses different polyester yarn structures on its interior and face to most effectively wick and disperse moisture. LIGHT WEIGHT - Lighter weight Phasic SL underarm panels improve thermal regulation and reduce bulk. 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.