[Auto Brake Sensing]-This bike brake light can double-click to switch between manual mode/auto mode.Both modes have brake sensing technology, and auto at maximum brightness to remind others.[Manual & Auto Modes]- The smart bike tail light will automatically turn off after when it detects no movement, and it is touched or the bike is detected moving, the light will automatically turn on again. Manual mode requires the taillight to be turned off by yourself.[Durable Battery & Charge Indicator]- The bike light has a built-in 420mAh - battery, which can last for 9 hours (maximum brightness) running time when fully . Click the switch in the off state, and the indicator light will indicate the remaining power, No worry about forget to charge.[6 Light Modes & Waterproof]- Bicycle brake light has six flashing modes: constant on(60lm), breathing flashing(50lm), slow flashing(50lm), fast flashing(50lm), rhythmic flashing(50lm), and flashing(30lm). IPX5 waterproof makes bicycle taillights suitable for any harsh weather.[2 Mounting ]-The bike taillight offers two different install - You can mount it under the saddle with mounting bracket or mount to the post with adjustable silicone strap.The bicycle taillight can quick install or detach. convenient to remove out from the bracket for recharging.color:Black:Aluminum + plasticPackage Contents:1 x bicycle taillight1 x USB cable1 x base bracket2 x anti- rubber pads1 x English manualOnly the above package content, other products are not included.Note: Light reflection and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.