The Hoopcheck is the fastest and most convenient way to measure your drum's hoop rise. Use the card to quickly measure the distance from the sound edge to the top of the hoop at each tuning point and easily determine if the rod needs to be loosened or tensioned further. There are 5 levels of measure and the Hoopcheck will work with any type of hoop. Turn the card vertically to measure the rise of a bass drum hoop. Keep the Hoopcheck in your wallet or put it on your keychain. The Hoopcheck card comes with a keyring and free shipping.