Features: USB rechargeable bicycle taillight and auto cut off when fully charged. High quality internal lithium battery,only need about 2 hours to be fully Charged while be used for about 12 hours. Long Steady Bright----2 Hours Slow Flash----10 Hours Super Flash----6 Hours Strobe Flash----8 Hours 4 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+ABS Size: Approx.65mmx29mmx23mm Light Source: XPE 3W LED Light Color: Black Output (Maximum): 300lm Lighting Distance: 30-50meters at night 3 Working Modes: High-Medium-Strobe Power Source: 800mAh Li-Poly Battery Charging Time: Approx.3hours Running Time: High: 3 Hours Medium: 5 Hours Flashing: 12 Hours Fit Handlebar: 20-40mm Rear Light (USB Rechargeable): Size: Approx.7.5×3×2cm Bulb Type: LEDs Brightness: 15 lumens Color: Red LED Light: White, Red Package Weight: Approx.50g Mounting Placement: Bicycle Seat Post Suitable Tube Diameter: Approx.12-32mm Package Included: 1×Front Light/1×Front Light + 1×Rear Light 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 possible, thank you！