Cycling Safety,JUSTUP High Intensity White 5 LED Bike - Bicycle - Cycling Flashing Rear Safety USB Rechargeable Waterproof Tail Light with 4 Modes USB rechargeable bicycle taillight and auto cut off when fully charged. 4modes:constant,slow flash,explosion lash and flash in order. High quality internal lithium battery,only need about 2 hours to be fully charged while be used for about 12 hours. Super waterproof,make you riding freely regardless of rain. High brightness and energy saving LED.