This is the Hattori Refresher Band Tape. Purchased for 1,100 yen (tax included). It's a tape that you attach to the underside of the hat's forehead band and replace when it gets dirty from sweat or foundation. It has antibacterial and deodorizing properties, suppressing the growth of bacteria while absorbing and neutralizing unpleasant odors caused by sweat, rendering them odorless.