Parking sensors provide visual or audible warning of your distance to objects behind you, making them great on longer vehicles, and those with poor rear visibility. This audible wired parking sensor kit consists of:4 wired ultrasonic parking sensors for complete coverageSensor control box21.5mm hole cutter sawSelf Adhesive velcro pads for the control unitAll wires compete with inline fuseFitting instructionsThe 4 parking sensors are wired into the control unit, which can be mounted in a convenient location at the rear of the vehicle, and connected to the reversing light power supply. The buzzer unit is connected to the control unit using the provided cable, and can be mounted anywhere it will be audible. As you get closer to an object, the buzzer will sound more frequently.Comes with 12 month warranty and immediate DispatchCE AprrovedSimple installation – Connect control box to reversing light to activate when reversing. Drill holes and install sensors. Everything else plugs in!