Note:1.The taillights can be charged with USB 2.The taillight is fully charged in 2h, and the taillight is always on for 3h 3.The taillights need to long pre the button to work!!!Features:USB rechargeable bicycle taillight and auto cut off when fully charged.High quality internal lithium battery,only need about 2 hours to be fullycharged while be used for about 12 hours.Long Steady Bright----2 HoursSlow Flash----10 HoursSuper Flash----6 HoursStrobe Flash----8 Hours4 modes: Long Bright, slow flash, explosion flash and strobe.Super waterproof, make you riding freely regardle of rain.High brightne and energy saving LED. Front Light (USB Rechargeable):Material: PC+ABSSize: Approx.65mmx29mmx23mmLight Source: XPE 3W LEDLight Color: BlackOutput (Maximum): 300lmLighting Distance: 30-50meters at night3 Working Modes: High-Medium-StrobePower Source: 800mAh Li-Poly BatteryCharging Time: Approx.3hoursRunning Time:High: 3 HoursMedium: 5 HoursFlashing: 12 HoursFit Handlebar: 20-40mm Rear Light (USB Rechargeable):Size: Approx.7.532cmBulb Type: LEDsBrightne: 15 lumensColor: RedLED Light: White, RedPackage Weight: Approx.50gMounting Placement: Bicycle Seat PostSuitable Tube Diameter: Approx.12-32mm If you don't know how to use the product or there is any problem with the product, please contact me to solve the problem first, I will reply as soon as poible, thank you!