The GUB Q-210S Smart Bicycle Horn has 4 adjustable volume levels up to an attention-grabbing 100db! This nifty little bike horn is also waterproof so you can just leave it on the bike.Features: USB Rechargeable Easy to mount 4 sound effects, 4 volumes IP65 level waterproof Ideal for 22 – 31.8mm handlebar Can be used on bicycles, ebikes, and scooters