Navy fabric: Thin cotton broadcloth Gingham check: Banshu-ori cotton Lining: Cotton sarashi (bleached cotton) - fabric that easily absorbs sweat. Thin and compact. Currently, head circumference: 40cm There is an opening for replacing the elastic, so it can be made smaller. The head circumference stretches to about 46cm due to the elastic. This is a prototype. There are some re-sewn areas in places that are not visible.