This is a high-end tail light from Lezyne. It's very bright at 400 lumens and has a built-in accelerometer that causes it to flash automatically when decelerating. I no longer need it because I switched to a radar-equipped light. Please refer to the official website for detailed specifications. Feel free to ask any other questions. ●Notes: Please check the photos and understand that this is a used item. Please purchase with no claims and no returns.