The lightweight and versatile Arc'teryx Cerium men's down insulated jacket provides exceptional warmth for its weight. It can be worn as a mid layer (second layer) or a standalone in cool, dry conditions. The Down Composite Mapping system maximizes the insulation benefits by placing the insulation in strategic areas. Durable, high performance with minimalist design to achieve lightweight. 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.