Keeping you Ready for the Road Ahead , the PHILLIPS & TEMRO 6' ZeroStart HD Cord set for Heavy Duty Block Engine Heater provides your semi truck with speedy winter starts, effectively providing direct heat to the engine coolant while staving off engine wear. OEM form, fit, and fashioned, this heavy duty engine heater replacement is tested and used for individual engine applications. FleetPride is your First Click in Heavy Duty .