This is one of the most useful pieces of gear I own. I have 2 of these now a medium and a large. Very weather proof. Very nice fit. Comfortable with or with out a base layer. I like a Patagonia light weight top with a zipper as a base layer on cold wet days. The vents keep the jersey from puffing out when the main zipper is opened up and give the in comming air a place to escape.