Castelli lightweight head thingysometimes simpler products are better and nowhere is that more true than on the lightweight head thingy the thin thermoflex fabric is extremely warm yet provides excellent moisture management and easily fits under your helmet the raw cut edges eliminate bulk under the straps and provide a comfortable fit featuresthermoflex fabricsoft flex fabric for lighter weight insulation as a neck warmer bandana or capsublimation printed fabricweight 43gbuycastelli clot