Just enough to take the edge off, for me anyway, on those 45-55 degree mornings. Super thin, doesn't change my helmet fit and pretty much disappears till you take it off.
Just as advertised, it fits under a helmet perfectly and fully covers the ears. My only complaint is that becuase it is so comfortable under the helmet I want to wear it more often, and it is sometimes too warm.
great fitting on my supposedly big head. covers the ears, warm, but not hot into the 30s and even 20s off road
