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 regardless of rain.High brightness 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: 20-40mmRear Light (USB Rechargeable):Size: Approx.7.532cmBulb Type: LEDsBrightness: 15 lumensColor: RedLED Light: White, RedPackage Weight: Approx.50gMounting Placement: Bicycle Seat PostSuitable Tube Diameter: Approx.12-32mmPackage Included:1Front Light/1Front Light + 1Rear Light If you dont 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 possible, thank you