Sensor diameter 22mmWorking distance 0-2.5mProvides only a sound signal, no LED screen.This device is a high-tech bionic product that uses waves emitted during operation and can measure the distance to obstacles through their reflections. The driver is warned in three ways: the digital display displays the distance to the obstacle (with accuracy in centimeters), the lit diode indicates the direction of the obstacle: L- left, M- middle, R- right and the alarm signal informs about different distances with different sounds. Maximum measuring distance 30cm-2m. Maximum current consumption 200 mA.INSTALLATION: The device may only be installed by a professional auto electrician. All connections must be insulated or otherwise prevented from moisture entering the connections. The sensors must be installed at least 50 cm from the ground and the distance between the sensors no more than 70 cm. Before installation, make sure that there is enough space for the sensor in the given location. Hole diameter 22.5 mm. Install the main processor in the trunk of the car. Connect the power cables as follows: black wire - car ground (minus), red wire - reversing light positive wire. Install the digital display on the cars dashboard in the drivers field of vision. Install the sensors on the cars rear bumper, connect the sensors to the control unit starting with the sensor located on the left side of the bumper to sockets a, b, c and d and the display to the socket marked DISPLAY.