If your hat isn’t a snug fit, the hat filler is for you…Made of foam cushioning, the adhesive filler sticks to the inside of your hat for a more appropriate fitReduces hat size by approximately 1-2.5 cmCan be used the whole way around your hat or just partially, if you are only wanting to reduce your hat size by a small amountPlease note, hat filler is applied to the inside of the hat crown, under the sweatband lining