The SR6 parking system emits short pulses of ultrasound waves, which then rebound from obstacles within their field of view. The rebounded signals are then received again by the sensors. The central control unit then evaluates the time delay of the rebounded signals and interprets the distance of an obstacle. The SR6 model includes 6 integrated reverse parking sensors and an audible siren. 2 Sensors for the front bumper and 4 sensors for the rear bumper. The system is hard-wired to the reverse lights of the vehicle allowing the system to automatically engage once the vehicle is in reverse. Initial tones confirm the selection of reverse gear, as the vehicle reverses nearer to an obstacle the tones become more frequent and remain constant at approximately 30cm from the obstacle. Installation is a easy as, simply drill the bumper with the supplied drill bit, and insert the sensors. Connect the 8 sensor wires to the control unit. Connect the supplied power (+) and ground (-) wires to the reverse lights.