Function:23 Function Backlight Model:YT-812B Material:ABS,engineering plastics, LCD display, electronic components, etc. Dual-line four displays Product Size:74*50*15MM; Power:a CR2032 button batteries (included) and solar charge Apply for the wire diameter within 0.2CM and Bicycle wheel circumference within 0CM-999CM (4-inch to 40-inch) Tip: magnets installed in the spokes,make the distance of magnets and the sensor is less 5MM. Function: 1. Display the momentary speed ranged from 0.0 km (mile)/h to 99.9 km (mile)/h. 2. Display the riding time ranged from 0'00'' to 999'59''. 3. Display the current time. 4. Display the average speed. 5. Display the highest speed. 6. Display a single riding distance ranged from 0.0 km (mile) to 999.9 km (mile). 7. Display calorie consumption ranged from 0.0 to 9,999.0 cal. 8. Display the total trip distance. 9. Display rotations per minutes (RPM) at work. 10. With imported sensors,stable performance, accurate speed and a wide variety of working temperatures ranged from -20 to 70 Centigrade. 11. Measure the wheel circumference. 12. Record the wheel circumference.