I bought this for working in the andes at 16,000 ft because its cold here. Material and quality is excellent; its a lot lighter and thinner than i expected. Its no vicuna sweater but it seems to be pretty warm. Size i thought was a little off, im 145lbs and 5'10 and a medium was too big for layering over a base so Ill be returning it for a small. Oh yeah, and it has kinda of a tall collar which is good for insulating precious neck zone. I like.