A magnetic drive that completely seals the switch compartment from the atmosphere for maximum leak protection is utilized in the Mark 1. The Mark 3 uses the same magnetic drive of the Mark 1, but it can be used for multi-turn applications with 1 to 25 revolutions, such as gate valves. A through shaft drive is incorporated in the Mark 4 making the unit a lower cost alternative to the Mark 1 for applications that are not as demanding. Product Highlights Transmitter 4-20 mA SPDT snap 10A @ 125/250 VAC, 1/3 hp @ 125/250 VAC, 1/2A @ 125 VDC, 1/4A @ 250 VDC, 4A @ 125 VAC direct drive with stainless steel visual indicator aluminum painted black