Mugen Pop Pop Endless Bubble Popping Keychain Ice (Clear White) Keychain has 8 buttons that simulate popping bubble wrap With every 100 pops, you get a surprise sound effect a dog bark, door chime, horn honk, and more! The white square of the keychain is approx. 2 inches by 2 inches Requires 2 LR41 button cell batteries (included) Age 8+