BONMIXC Bike Bell Brass Mini Easy to install - fits for bicycles handlebar tube outer diameter with 21mm - 23mm (0.83inch - 0.90inch) Sound - the bike bell is made from brass, bring us a clear, sweet, loud sound For bike type - fits for any standard straight bicycle or stunt scooter handle bar, mtb bike bmx bike etc. Dome diameter - 33 millimeter (1.3inch)