The perfect skull cap requires a few key design elements. The product has to be lightweight, well vented, comfortable, quick drying and most importantly low volume so it fits under your helmet. Castelli achieved all of these points with the Summer Skull Cap. The body of the cap uses 3 anatomic panels, all of which are constructed of a super vented fabric called Velocity. This proprietary fabric wicks well and dries super quick. Most importantly, it is very low volume. These three panels are stitched together using flat seams. The fourth and final panel of the cap comes in the form of a 3/4 headband. It's job is to prevent sweat and perspiration from getting into your eyes and face during ride time.

Castelli has always done caps well and the Summer Skullcap is another example at perfection in a cycling garment. We are unclear of anyway to improve on this product.
One size fits all. Choose color.