Flexible layers are a key part of your cold-weather fitness kit, and little else tops a Crosslayer 1/4 Zip Mock for versatility. Wear it as a mid layer in balmier winter temps or as a robust base layer in blistering cold ones. From the windproof front panel and smooth, easy-layering outer to the heat-holding grid fleece inside, this quarter zip is built to help you maintain warmth as you hike, trail run or bike.