Electric Bike Horn Usb Rechargeable Bicycle Bell 120 Db Invisible Cycling Alarm Loud Horn Waterproof 3 Modes Alert Ring For Mountainroad Bike Scooters Handlebar 22-318Mm (Black)Ytuomzi Electric Bike Horn USB Rechargeable Bicycle BellSMALL BUT LOUD - This electric bike horn is build in voltage boosting circuit, ringing sound up to 120dB,lond enough ..