Intelligent brake sensor and easy installation: automatic switching to high light mode when braking, ultra-bright for 5 seconds lights warning back driver to improve your safety. You can mount it under the saddle with metal bracket or attach it to the seat post with adjustable silicone strap. (We offer 2 variants of bracket mounting)Four light modes and LEDs with high light bag: There are 4 light modes for your choice, enjoy your cycling as you want, high lumen COB LED bicycle rear light makes you more visible, it is a perfect bicycle light for night riding.Automatic on and off to protect the battery: this intelligent bicycle rear light with motion sensor and light sensor, it is automatically switched off when no movement is detected after 30 seconds. As soon as you touch it or detect that the bike is moving, the light will automatically turn on again. Even if you are driving under the sunlight, the rear light will automatically turn off because the light sensor is working, if you want to drive during the day and the tail light needs to work all the time, please choose mode 3 and mode 4 to avoid the light sensor.Adjustable brightness and battery indicator: the brightness of this bicycle rear light is adjustable, in the steady on mode, just long press the button to adjust the brightness you need, it built-in 400 mAh Li-ion battery, it can last 50 hours (is affected by the brightness you setting) running time when fully charged. Four blue indicator lights, each shows 25% capacity, no longer forget to charge.Aluminium housing and IPX6 waterproof: made of aluminium alloy shell, this bicycle rear light has a beautiful touch and awesome appearance. It is waterproof/dustproof and shockproof, suitable for any harsh working environment.