1.USB rechargeable: The electric bike horn supports USB charging for longer battery life, and the built-in 200mAh lithium battery will let you use it, and the USB cable can be fully charged in 1.3 hours. It can play 2000 times continuously, enough to run for 60 days 2.Bicycle horn: The electric bicycle bell with the sound volume up to 125 decibels can effectively warn nearby people and vehicles of traffic accidents even at a distance 3.Widely used: The electric bike bell suitable for handlebar diameter 22.2mm and 31.8mm, and you can fix it with silicone bands, suitable for road bike, mountain bike, children's bike, city bike, bicycle sports, cruisers, mountain bikes, BMX, e-bikes, scooters, etc 4.Anti-theft alarm function: Long press the switch for 3 seconds to turn on the anti-theft function with two alarm sounds, press the switch for 3 seconds to turn off the anti-theft function with one alarm sound once, when triggered by again, the alarm will sound again