ADVANCED DESIGN. The Tail Light is built in 330 mAh rechargeable lithium battery. It comes with a CHARGING CABLE that charges from your computer, power bank or any device with a USB port. 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. 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. 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. BUY WITH CONFIDENCE: Ascher is committed to providing our customers with high quality products, we are dedicated to ensuring your fully satisfaction. Please contact us when you have any problem, we will solve the problem for you as soon as possible.