Housed in a tough composite case, this unit is designed to prevent damaging voltage spikes & surges reaching delicate vehicle electronics. It clips across the battery terminals & permits processes such as welding & plasma cutting to be carried out without the danger of damaging the vehicle’s on board electronics. Fitting is recommended before any routine workshop maintenance. The device shows a green light when operating correctly & a red light for a fault. Fitted with heavy-duty, fully insulated battery clips.