Display the riding mileage, time and speed. Examine the total riding mileage, total time and the fastest speed. Temperature, and clock function, display the voltage of battery and auto-display the maintenance of bicycle. Add-subtract speed is displayed with movements over-speeding warning, more safer. Auto-lamp, when it is night. Size: 9. 1*4. 8*3. 8cm Carton size: 49*30. 5*31. 5cm (120pcs / ctn) G. W: 19. 6kg Moq: 5000pcs.