Varitherm base layer Flex Weight Top helps you stay outside longer with its lightweight warmth and flexible fit.Champion Vapor technology with X-Temp™ dries faster as your body heat rises so you always keep your cool.Wicks sweat away from skin for cooler comfort.Ultra soft brushed back fabric helps trap body heat without bulky layers.Close-to-the-body fit flexes and stretches for total mobility.Chafe-resistant stitching is soft on skin.Thumbholes help keep chilly winds out.