[【Horn Function】Press button 2 to ring the horn three levels of volume adjustment(80-130db)button 1 to increase the volume and button 3 to decrease the volume. 【Anti-theft alarm】Press and hold button 3 for 3 seconds the horn will sound and enter the pre-armed state; wait for 10 seconds the horn will sound again and enter the anti-theft monitoring state. If the vehicle is shaken or vibrated the horn will continue to sound for 10 seconds. 【USB rechargeable and long standby time】Comes with a charging cable you can use the USB port to charge the horn the full charge time is about 1.2 hours the battery capacity is 250 mAh available for 20-30 days. 【IPX6 Waterproof 】Can be used in rainy days suitable for bicycle road bikes mountain bikes electric scooter. 【Easy to Install & Remove】Easy to install and remove put the silicone strap fixed on the handle. Suit for 0.86"-1.25"(22.2-31.8 mm )diameter bicycle handlebar]