[Small size] is as large as an hour, it can be concealed to the inside of the handlebar, it does not affect handlebar brakes, gear change or other operations<br> The USB cable and the long-lasting power] are equipped with a standard Android USB charging cable, it can be completely charged in 1 hours and can play 2000 times continuously on a single charge, which is enough to work for 20-30 days<br> Multiple ringing sound] This bicycle horn has 4 sound mode, you can change the ring sounds by pressing a button and there is always a ringing sound that suits your environment<br> with full protection] This electric bicycle horn, high impact resistance + high heat resistance + flame retardant and other features ABS + PC material uses featuresOutdoor bicycle meets your needs<br> Easy to install] It is easy to install with silicone buckle straps and is fixed, does not require toolsYou can install or remove the electric bike horn in 20 seconds to your bike's handlebarIf you are not sure, you can also read the English guide.