Belay Jackets:
Jackets designed to provide extra warmth on stances. Can also be used as general warm jackets for wandering around town in.
Mid Layer:
Pull on tops, light jackets and vests that can either provide extra mid-lay warmth or light weight outer layers for moderately cold conditions.
NB Some of these products are very lightweight indeed. Using a rucksack with them, without a protecting outer layer, is not recommended.