A thermal jersey is a key component to winter riding, and the Prime-Series Thermal Jersey is no exception. With Polartec� Power Grid� fabric, it's not only extremely warm, but also lightweight, stretchy, and downright comfy. 3 back pockets provide ample storage for your cold weather riding gear. 4-way stretch fabrication has allowed us to create a Slim Fit jersey for winter riding. Fabric Content: 91% Polyester, 9% Spandex Knit. Fabric outer surface is engineered to disperse moisture for fast evaporation. Hydrophilic next-to-skin surface absorbs sweat and transfers it to the outside of your garment. Lightweight garment keeps you extremely warm while preventing excess weight and bulkiness on your body. Polartec� Power Grid� generates targeted touch points to manage moisture while grid design creates improved breathability.