TPS151GT10-000 Coolant Pre-Heater for Diesel and Gas Engines, Construction Equipment, Trucks, Marine and Industrial Applications. Suitable for liquid-cooled engines up to 500 cu-in / 8.2 L, using coolant hose systems around 5/8″ (≈16 mm). This model does not include a plug. Requires hard-wiring to a 120V circuit.