Need to make your hat smaller? Add our easy foam hat sizing to any of our costume hats to customize the fit or adjust the size to fit kids, teens, or adults with smaller heads. Decide how much you need of our 1/4-inch-thick self-adhesive foam, available in 6", 12" or 24". Just trim with scissors down to the size you need, peel off the paper backing, and stick the foam inside the hat brim! One layer of foam takes a hat down one size, or put a smaller piece in front, back or on the sides to prevent slippage in targeted areas.