Light sensor, only light up in dark environment and when wheels are spinning

Automatically turn off either when it is too bright or after the wheels stoped 10 seconds

Installs on standard tyre air stem valve of cars, motorcycles or bicycles

Easy to install, twist off your original valve cap, and replace with our valve cap LED light

Color of the light: color change, flashing

Some color are shown below: Blue, red, green.....

http://www.1powershop.com/en/lights/2-x-bike-car-tyre-valve-cap-colorful-lighting-wheel-led.html