Long battery endurance, low consumption Super Long Battery Duration: 4000mAh built-in rechargeable Li-ion battery and Low energy technology together bring you up to 3000 hours working time (headlight off ,only odometer work).it offers 6/12 working hours when you turn on the head light. USB chargingPlease note, it can not be charged by computer USB Port, only Mobile phone charger and Power Bank charger.Or it will continuous restart. Bike computer: Bike speedometer with accurate tracking on speed and distance helps you to get more fun of your cycling trip or easily achieve your fitness goals. 12 FUNCTIONS BIKE COMPUTER: top/current/average Speed, distance, lighting, LCD back light, clock, time, calorie, auto turn off/data storage, power saving etc; Bright back light 2.1 big screen LCD display with sustained backlightallows you to read the digital clearly in the deep dark night or in the long tunnel.Keep press SET key for 2 seconds to turn it on, keep press SET key for 2 seconds to turn it OFF. Spotlight / Floodlight the rang of spotlight make the bright more longer, the floodlight make the bright more wider. to make sure you will have a clear vision at night. Doule T6 LED800 lumen headlight with 3 modes(bright light; Bike Bell120dB speaker provide a clear warning for passers-by riders and cars. Please enjoy cycling with this wonderful gadget in the anytime to feel your speed! Wired control. There are 3 kinds of sound mode. 120dB. Long press button 8 seconds to select the sound mode that you wanted. Suitable for all kinds of users.