FIT
A loose fit will allow layers to be worn underneath. A tighter-fitting fleece is used as a mid-layer.
POCKETS
Jackets and heavyweight pullovers will most likely have handwarmer pockets. Lighter garments designed to be worn as a mid-layer may just have a Napoleon chest pocket or no pockets at all.
HOODS
HOODS PROVIDE EXTRA WARMTH AND ARE DESIGNED TO BE TIGHT-FITTING SO