This Avantco 17816442 defrost heater fuse is a perfect replacement for the one that came with select Avantco A-19F, A-49F, CFD, SS-2F, and SS-3F units. It is a vital part of your unit to melt accumulated frost off your unit's evaporator coil surfaces and warm the drain pan, which allows the condensation to drain without refreezing. A broken probe can prevent your unit from operating efficiently, so be sure to replace it promptly.