Brake Sensing: The rear light is equipped with a brake sensing feature that automatically turns on when you apply the brakes, ensuring maximum visibility and safety. Waterproof Design: The rear light is designed to be waterproof, making it suitable for use in all weather conditions and ensuring that it remains functional even in the rain. LED Charging: The rear light can be via LED, eliminating the need for complicated wiring and ensuring that it is easy to install and use. Convenient for USB Charging: The intuitive battery display and low battery reminder let you know the battery status at any time for a smooth ride.Buckle installation design allows you to easily remove it for charging,Can be via computer, charger or mobile power. EASY AND SIMPLE MOUNTING SYSTEM: With saddle rail and seatpost mounting options, the bicycle rear light can most fit any bicycle. With the design of bracket and taillight, it's very convenient to twist the light in & off the base cap for charging. Colour:Black & Red Material:Plastic Package Contents: 4 x Bicycle taillights Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.