[SAFETY FIRST]This loud volume & mini size electric bike horn can reach 120 db which is loud enough to alert anyone or even people in a vehicle to your presence. Perfect bicycle accessories for you or your kids.[EASY TO INSTALL & REMOVE] Easily mounted and secured with the stretchable straps to fixed on the handle, install or release it from the bike handlebar within 10 seconds. Suit for 0.86″-1.25″(22.2-31.8 mm )diameter bicycle handlebar.[WITH IPX4 WATERPROOF FUNCTION]bike horn can use for mountain bikes, road bikes, walking bikes, electronic bikes, or scooters, with IPX4 waterproof which can be used on rainy days[3 VOLT-CR2032 BUTTON CELL]CR2032 button cell no mercury added (Comply with EU environmental standards), leakage protection (longer lasting use), can withstand a maximum continuous current of 20mA, so our bike bell can ring continuously. It is measured to last 5000 times of ringing. It can be used for a long time and does not require frequent battery replacement.[60-Day Mone