You don't have to take it off and put it back on all day. 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 knit in body and sleeves - Provides breathability where you need it most.1/2 Front Zip - Allows for easy dressing and comfortable layering.Built-in T-shirt holder – Located virtually on the user's right side.