Voltage:DC10V-12V Power:4W(max) Temperature;-40℃- 80℃ Detecting range:0.1m-1.5m Volume:85dB Sensor: 4 Eyes ,available in multi-colors Screen:trapezia ParkMaster works by ultra-sounds and sets off automatically when you go into reverse. The effect is that of an electronic safety shield that spans from 30 cm to 1.5 metres behind your car. The distance of the obstacle from your car is signalled by the beeper frequency. The closer the obstacle is, the faster the acoustic signals become: the system beeps just long interval when an obstacle is 150-cm away (safety zone), a repeated beeping starts when the obstacle is between 90 and 30cm away (alert zone), whilst a constant beep is emitted when a vehicle enters the maximum alert zone.