USB Rechargeable HornThe electric bicycle bell built-in 300mAh lithium battery, 1.2 hours fully charged can use for about 30-60 daysringing about 4000 times and standby for 180 days.4 Levels Volume AdjustmentThis electric bike horn is designed with 4 levels of volume, the bell can reach 80-90-100-120dB, which is enough to warn the pedestrians around. Suitable for different environments.4 Sound ModeClassic metal bell Sound, Vibrantion bells sound, Steam whistle sound, Horn sound, for different situations.Separate Switch DesignControl switch and bike horn are separated. you can install the bell to any position you like and install the control switch right next to your thumb, which can keep you hand still on the bar when you press it. Very ergonomic design, Keeps you riding safely.Easy to Install & RemoveSimply put the bike bell to the handlebar and use the silicon buckle to fixed on the handle. Suitable for 0.86"-1.25" (22.2-31.8 mm) diameter bicycle handlebars