The adjustable strap design empowers our sleep hat can fit heads of most sizes and meet the need of fastening head and maintaining your head safe and stable for a specific post-surgical treatment purpose. Soft and breathable. The practical satin silk lining reduces the friction and the water-loss of your hairs when your head is exposed overnight. Your smooth hair will be well protected and saved from dry-out. This property makes our sleep hat a good helper for those who are trying to tame their frizzy hair or experiencing hair loss. It can work as the workout hat when you are running, cycling and playing the basketball, or as a daily head-wear when hanging around or on windy days.