The sensor bike's taillight is waterproof and safe to ride at night. Features: The built-in high-precision sensor, combined with depth algorithm, can detect the tail lamp quickly even if the brake is slight. According to the different horizontal angles of the seat tube, it will automatically calibrate the depth algorithm to identify the uphill and downhill sections, and maintain the braking accuracy at all times. One key switch between manual mode and intelligent mode. It can be used to filter the small rolling motion and small bumpy road section. But too large a hole to slow down the shock zone will still active the brake light warning. Ride fearlessly whether it is rainy or sunny. Specifications: Material: ABS+PC Waterproof rate: IPX6 Bulb: COB LED, eye friendly Batterys: 350mAh Li-batterys, USB charge low batterys indicator Runtime: steadys light 15h, breathe flash 18h, slow flash 25h, qucik flash 27h, rhythm flash 27h, ECO flash 48h Type: Saddle Light, Seatpost Light (optional) Package size: 205 * 65 * 43mm / 8.1 * 2.6 * 1.7in Package weight: 70g / 2.5ounce Packing List: 1 * Bicycle Flashlight<br> Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement. Sold by-Minnanxin