The Arc'teryx Rho LT Zip Neck weighs 185g and uses Torrent 190 fleece with Polygiene odor control for cool-weather base layering. This is one of Arc'teryx's most popular baselayers, and for good reason. The brushed fleece interior feels soft against skin, while the smooth

The Arc'teryx Phase SL Zip Neck weighs 110 grams and dries faster than any other baselayer I've used. Phasic SL fabric, 100% polyester, sits tight against skin and pulls sweat off your body before you notice it's there. The deep front zip and tall