Rechargeable Smart LED Tail Light

This Wicked Cool Smart Tail light Acts as Both a Running Light and A Brake Light.  Auto sensing motion technology identifies when the brakes are applied and alerts any  riders or cars behind you that you're slowing down.   Mount to seat, seatpost, rear rack or seatstay.   IPX4 waterproof design 16 LED's Auto on and off function senses motion Rechargeable via USB Cable/Port Double Your Safety Factor. Put One on Each Side!   Specifications: Material: aluminium alloy + ABS Battery: 3.7V, 350mAh Charge time: 2 hours and 20 minutes Charging current: 5V, 280mA Waterproof: IPX4  Modes: manual / automatic Item size: 1.2 * 1.1 * 1.2in Item weight: 1.0ounce Includes: Smart Tail LightUSB Cable Manual Installation Kit