Designed to cut off power from towing vehicle to caravan battery and fridge when no charge is available. Suitable for vehicles with multiplex and canbus wiring systems. Avoids discharge of car battery when running a caravan ‘fridge and charging the leisure battery. Relay switches on at 13.5 and off at 13.2 volts and features heavy duty terminal blocks. Comes with instructions for fitting to touring caravan 12S and 13 pin systems.