[High volume electric bicycle horn]-- The maximum sound of the bicycle speaker reaches 120 decibels. When you drive in a noisy environment, complex road conditions are subject to collisions. This oversized horn sound is strong enough to effectively alert pedestrians and surrounding drivers to avoid traffic accidents. [Anti -theft alarm]-- Press the left button (locking button) for a long time to enter the alert state. If someone touches or pushes the bike, the bike alarm immediately emits a strong and continuous alarm sound, so that thieves do not dare to approach. Press the right button (unlock button) to leave the anti -theft state. [Long waking time]-- Electric bicycle horn alarm, the capacity of the integrated horn is 250 mAh. It can be fully loaded in 0.5 hours, can be reused 1000 to 1500 times and operate for 20 to 30 days. A charge can be used for a long time, you don't have to worry about running out of energy the next time you use [Waterproof IPX4 and USB loading]-- The bicycle bell is waterproof and can be used on rainy days. The electric bicycle horn alarm adopts the USB load and can be loaded in different ways, such as sockets, power banks and laptops. [Easy installation]-- The doorbell does not need to be installed with complicated tools, just fix the silicone bicycle horn alarm strap with the handle, and the strap is elastic and durable. This doorbell is suitable for bicycle handlebars with a diameter of 22.2 to 31.8 mm, which can be applied to mountain biking/electric scooters/racing cars, etc.