Craft's Pro Zero Extreme is a thin, lightweight, extremely elastic channel-stitched fabric that combines two high-tech fibers: Coolmax Fresh FX and Thermolite hollow fibers. Resting on the skin is Coolmax Fresh, a hexa-channeled fiber that pulls moisture away from the skin. This fabric also prevents the garment from retaining odors. The garments outer layer utilizes Thermolite hollow fibers which ventilate and use a capillary action to pull moisture further away from the skin. This is a thermal base layer that pulls moisture from your skin as quickly as a summer weight piece.