High volume electric bicycle horn. The maximum sound output reaches 120 decibels, providing a loud and powerful alert signal. Ideal for use in noisy environments or complex traffic conditions, this horn helps effectively warn pedestrians and drivers to help prevent accidents. Anti-theft alarm function. Long press the left button (lock button) to activate the alarm mode. If the bike is moved or touched, a loud and continuous alarm will sound immediately, deterring potential theft. Long press the right button (unlock button) to deactivate the alarm system. Long standby time. The built-in battery has a capacity of 250 mAh, charges fully in 0.5 hours, supports 1000–1500 recharge cycles, and can operate for 20–30 days on a single charge. Provides reliable performance with extended usage between charges. IPX4 waterproof rated and USB rechargeable. Designed to withstand splashing water from any direction, making it suitable for use in rainy conditions. The device features USB charging compatibility, allowing convenient charging via wall adapters, power banks, or laptops. Easy installation. No tools required. Simply secure the silicone strap around the handlebar. The elastic and durable strap fits handlebars with diameters between 22.2 mm and 31.8 mm. Compatible with various bicycles, e-scooters, mountain bikes, road bikes, and more.