Originally posted by Kris: Most wool does not stop wind per se. It really has to do with the tightness of the knit. Felted wool IMO works a little better at impeding wind penetration. Some companies include Windstop, Gortex or other impervious membranes for this very reason. I often wear a brushed nylon goose down vest underneath my wool as a wind buffer. Many other things will work in a similar way...layering is key.Kris