Review on M1A2 Circuit: A Reliable Waterproof Resettable Amplifier for Industrial Electrical Applications by Neil Bodell

ordered this to install an amplifier on a boat using 4AWG cable. First I put threaded plugs on the wires, then red elastomer o-rings that fit very snugly against the wire insulation (it was a bit difficult to tighten at first). Then I stripped the wire, plugged it into the switch and tightened the set screws. Then slide the o-ring, close the breaker and tighten the end caps. The result is a nicely compressed O-ring that is good at keeping out moisture. The switch worked as advertised.