The Mens Terramar Thermolator II Crew is a medium weight top that works great on its own and as a layer. Made with microfilament polyester and spandex yarns, the Thermolator II provides incredible softness with 360 stretch for active comfort. An excellent base layer, the Terramar Crew features functional thumbholes for easy layering, mesh inserts for air flow, and Qwik Dry Thermoregulation Technology and antimicrobial properties. Other features include set in sleeves, drop contoured back panel, UPF rating of 25, and flatlock seam construction. The Mens Terramar Thermolator II Crew is an ideal baselayer for a range of cold weather activities.