Product information: Bicycle whose handlebar is 22-31.8mm in diameter Material: ABS PC Weight: 40g Size: 49*66mm Decibel: 110-120db Battery capacity: 280mAh Charging time: 1.2 hours Charging voltage and current: 5V-250mAh Sound type: Whistle, horn sound, alarm sound and information sound Package content: 1 * electric horn with control button 1 * rubber band 1 * charging cable Note: Please remember to close the waterproof cover after charging Indicator light: red light when charging, green light when full power 4 tones : whistle, horn sound, alarm sound, information sound (volume can reach 120db) USB rechargeable: 1.2 hours charging ring for 2500 times, which is enough to work 20-30 days Easy to install: just install the bell by sliding the Rubber band buckling IP65 level waterproof anti-dust anti-drop (please remember close waterproof cover after charging) Suitable for mountain bike, road bike