High volume electric bicycle horn. The maximum sound output reaches 120 decibels, providing a loud and powerful alert suitable for noisy environments and complex road conditions. This horn effectively alerts 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, deterring potential theft. Long press the right button (unlock button) to deactivate the alarm mode. Long standby time. The electric bicycle horn features a built-in 250 mAh battery, fully rechargeable in 0.5 hours. It supports 1000–1500 charge cycles and can operate for 20–30 days on a single charge, ensuring reliable long-term use. IPX4 waterproof rated and USB rechargeable. Designed to withstand splashing water, this horn can be used in rainy conditions. It features a USB charging port, allowing convenient charging from various sources such as 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 from 22.2 mm to 31.8 mm. Compatible with mountain bikes, electric scooters, road bikes, and more.