Zacro Bike Computer,Original Wireless Bicycle Speedometer with Compass Key Ring,Multi FunctionBike Odometer Cycling We have updated the version with Stronger Magnet and 2 back-up batteries , and the appearance will be more concise and easy to use; Easy-to-read LCD display : big LCD display with big numbers so you can easily see the stats even you are riding Portable and convenient: It is very small and light but you can have the basic info you need in monitoring your biking activity, measuring speed ,distance, riding time, maximum speed and average speed Wireless and water resistant design: You attach the sensors to your front fork and your spokes and you're good to go The backlight can be set in either green and white color Besides the fact that it is suitable to all types of bicycles: road cycling, mountain biking, folding bike, common bicycle, We have also attached a Compass key ring