Product Overview Replacing a tired or sticky master switch is one of the cheapest reliability upgrades on a DC system. The MT018 is built for exactly that job: a 150 amp two-position rotary isolator that drops into the same panel opening and gives a clean, positive break between the battery and everything downstream. There is one dial movement to learn. ON closes the circuit, OFF opens it, and each end position has a machined stop so the contact cannot sit in limbo. For a