Looking for the perfect base layer for cold-weather workouts? The SRB LS 01 in black is the one. It’s designed to keep you warm during chilly runs and cool you off post-sweat – without the bulk. Crafted with a four-way stretch and moisture-wicking material, complemented by strategic mesh panels, the SRB LS 01 keeps you agile and cool no matter what the elements throw your way.