The included base securely locks the computer into the slot, preventing falls from bumpy roads, mounts the sensor on the front brake, and the magnets on the spokes, 4mm from the sensor. Replaceable battery, easy to open battery case with coin help, coin not included [Multifunction]- Automatic sleep/wake, show current speed, max speed, average speed, distance, distance traveled, time, stopwatch, calorie consumption, temperature and clock. [Easy Installation and Wide Application] bike computer can be installed in just a few minutes. Customizable to most common tire sizes for accurate statistical tracking. The small size, light weight and wireless design suitable for most types of bikes: road bikes, mountain bikes, folding bikes, regular bikes, pit bikes, etc. [Waterproof]Small size, light weight, easy to transport and install. The waterproof design makes it more comfortable and durable, even in the rain, you can still enjoy your trip. color:Black : ABS Package Contents: 1 x bicycle computer 1 mounting accessories Only 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.