To be inserted along the power supply line, immediately before the depth sounder, GPS, Plotter, radiotelephone, etc. Suppresses interference from the alternator or from on-board equipment requiring a large amount of current (anchor winches, radar, etc.) and protects instruments from current discharge. 12 V power supply, capacity 60 W (5 A), tripping time 5 nanos, peak current 4500 A, dissipated energy 45 joules.