Wicking, warm, and odor - resistant, the Pines Microgrid Ultra - Lt Baselayer Balaclava Top is a winter essential we won't leave for the hill without. We crafted this unique, ultralight baselayer from a stretchy blend of polyester and spandex to keep us moving in warm, dry comfort, and outfitted it with thumbholes and a built - in balaclava hood to bolster our defense against icy conditions.