Immersion style heater preheats oil in wet sump oil pan or dry sump tanks to reduce overall warm up time and improve lubrication during initial start up. 5/8" diameter stainless Steel sleeve inserts into pan or tank and secures with a welded on 1/2"NPT brass screw-in fitting. 120-volt operation. These are not thermostatically controlled, units will continue to heat as long as they are plugged in.