You use intermediate layers under the shell jacket as an extra, warming layer. They are available with or without a hood and in models that suit men, women and juniors. Choose which materials the intermediate layer should consist of and the size of the model. Wool fiber insulates well and stops sweat odor, synthetic fiber such as fleece is good at transporting moisture away from the body. On hot days, no extra jacket is needed, then the intermediate layer works well on its own.