ADVANCED DESIGN. The taillight has a built-in 330mAh rechargeable lithium battery. It comes with a CHARGING CABLE that charges from your computer, power bank or any device with a USB port. FOUR LIGHTING MODES: The taillight has a one-button switch with four different lighting modes depending on your preferences. Includes full brightness, half brightness, fast flashing and slow flashing. EASY INSTALLATION: With a convenient removal button, you only need to slide the light on and off the bracket without removing the entire mounting bracket. The silicone mounting strap for the taillight is designed with four openings that fit snugly around most handlebars and seat posts. BE SAFE WHEN CYCLING: The taillight emits an eye-catching wide-angle beam that can be seen from several blocks away, you don't have to worry about being hit by others. BUY WITH CONFIDENCE: Ascher strives to provide our customers with high-quality products, we are dedicated to ensuring your complete satisfaction. Contact us when you have any problems, we will solve the problem for you as soon as possible.