One layer that you don't have to take off and put on all day long. It adapts to the ambient temperature – it warms up when it's cold and dissipates excess heat as it gets warmer. UA Storm Technology – Repels water without compromising breathability. Durable woven fabric on chest and collar – With lightweight fleece insulation for warmth without bulk. Smooth and breathable knit fabric on body and sleeves - Provides breathability where you need it most. Secure zippered pockets – Allow you to store small items or warm your hands. Built-in T-shirt holder – Located virtually on the user's right side.