Adhesive backing. Sticks to most smart phones. Pocket doubles as a wallet. Convenient for credit cards, driver license, hotel room key, etc. Will not demagnetize your cards. Thin and light weight.Adhesive backing. Sticks to most smart phones. Pocket doubles as a wallet. Convenient for credit cards, driver license, hotel room key, etc. Will not demagnetize your cards. Thin and light weight.