Easy to install: Easy to mount and secure with the stretchy straps. No tools needed The volume of the mini size of the sound volume, electric doorbell buzzer, can reach 120dB, which is loud enough to alert of your presence. Perfect bicycle accessories for you or your kids. Eco-friendly, our Bicycle Bell built-in 280mAh lithium battery, USB rechargeable, rings 1.2 hour charging time for 2 000 times, 20-30 days battery life. Separate switch design: The control switch and the bicycle horn are separated. You can install the control switch right next to your thumb, convenient and safe. One key switch, 4 sound modes on the upgraded version. Durable with full protection, IP65 level waterproof + dustproof + anti-drop, the bicycle horn fully meets your needs outdoor cycling.