The Arc’teryx Atom Heavyweight Hoody (Revised) men’s hooded insulated jacket is breathable enough to be used as a warm mid layer on cold wet days and protective enough to be worn as a standalone while hanging out at camp. This mid layer features a synthetic insulation designed with quick dry times, durability and retains warmth even when damp. Layering is the key of keeping you dry, warm and using your energy efficiently. Put into the right systems, a good sequence of layers moves moisture away from your skin, conserves or dissipates heat and provides you with weather protection. Here they are. The first layer, worn next-to-skin will provide warmth and quickly move moisture away from your skin. Then, the second layer, is the insulation and fleece, that provides warmth while also dissipating heat during periods of high output. And finally, the third layer, the shell, which is the most weather-protective layer, worn on the outside of all other layers.