Advanced Design: The tail light is built in a 500 MAh, 3.7V rechargeable polymer battery. It comes with a charging cable that charges from your computer, power bank, or any device with a USB port. Six Light Modes: Intelligent rear lights-6 gears (strong light, medium, weak light, strong flash, slow flash, fast flash). Easy Installation: Just like the picture shows, it is very easy and convenient to install, no tools are required for mounting it and it takes only seconds to set it up and remove. Plus, it allows 360?a adjustable. Universal fit for anything you can think of Bicycles, strollers, dog leashes, hats, helmets, backpacks, bags. Get Riding Safety: The tail light emits an eye-catching wide-angle beam (allowing 100 m vision) that can be seen from blocks away, need not worry about being knocked over by others. Specification: Material: ABS Color: Red Brightness: 100 elm Discharge Time: 4.5 hours of strong light, 6 hours of medium light, 14 hours of low light, 25 hours of slow flash, 28 hours of fast flash, 6 hours of strong flash Charging Time: 0.5 hours Product Size: 6.3 x 2.7 x 2.8 cm Packaging: 1 x light, 1 x USB cable