Castelli make some very nice technical cross-over products that look and perform great on the bike, but also have a finished look and style that feel right anytime. The GPM Beanie is a perfect example, as this low volume wool blend knit hat is great for cold days on and off the bike. With the natural thermal and wicking properties of wool, and the added comfort and moisture transfer of polyester, you stay warmer and drier. The pro cyclists of Team Ineos love the performance and versatility.
The wool blend has been knitted in fine gauge, with compact, slight ribbing and texture on the top panels, and a slightly wider, looser knit with more stretch on the bottom band. Complementing that band is an internal polyester fleece liner that feels soft against the skin and ears, while increasing the overall moisture transfer rate for greater comfort. The panel has liner has some stretch to match the wool, so the dual materials feel natural.
As far as helmet fit, you will want to make sure you have about 1/4 helmet size of adjustment to work with. The peak is a little taller and overall there is more bulk than a thin cycling hat. If you normally have very little adjustment in you helmet size, the GPM may not work for that helmet. Don't worry, the GPM Beanie features clean, embroidered logos that look great off the bike. You'll get your money's worth either way.