This flight cap can be used as an inner cap for helmets. Free size (approx. 55-60cm) Color: Black This is recommended because long-haired caps can be uncomfortable when you sweat. The brim has a wire in it, so it won't shift in the wind. It's thin, so you can wear it without changing the size of your helmet, keeping you warm and, above all, looking cool. Perfect for those who use shorty or jet helmets, as well as Harley and American riders, and for classic styles. Helmet is not included. If you purchase it with a helmet, you will receive a 200 yen discount, so please comment if you wish.