Product description Simple control button conveniently located on top of the light for easy access. Click the button to change light modes and cycle through the light modes to TURN OFF. Smart charging ensures longer battery life - Automatic, fully charged cut - off system. 1.ADVANCED DESIGN The Tail Light is built in 200 mAh rechargeable lithium battery. Allowable Power bank or any device with a USB port use. 2.FOUR LIGHT MODE OPTIONS: The Tail Light feature an one-touch switch with four different lighting modes depending on your preference. Include full brightness, half brightness, fast flashing and slow flashing. 3.EASY INSTALLATION: With a convenient one-touch dismount button, you just need to slide the light on off the mount without removing the whole mounting bracket. The silicone mount strap for Taillight is designed with four openings that tightly fit around most size handlebars and seat posts. 4.GET RIDING SAFETY: The tail light emits an eye-catching wide-angle beam that can be seen from blocks away, need not worry about being knocked over by others. 5.EASY TO USE Hook onto your belt, running gear, reflective vest, backpack, dog collar, harness, or anywhere on your clothing. Mount to your bicycle, helmet, skateboard, scooter, stroller, wheelchair, or anywhere you can imagine. 6.[Function]: Press and hold for 2 seconds to enter, click to shift to highlight - left and right wheel flash - burst flash - left and right jump flash - constant light = four-speed cycle. Press and hold for 2 seconds Size: length 75* width 30* height 20mm [Applicable]: Seat tube diameter: 12-32mm Package Contents: 2 X Tail lights 2 X USB cables