Mr. Heater F273117 39in Thermocouple Lead features copper construction and brass fittings for durability. It prevents unburned propane release for added safety. The thermocouple replacement is flexible for easy replacement. It fits most Mr. Heater top tank models. Mr. Heater Tank Tops models: MH12, MH12C, MH12T, MH12CS, MH12TS, MH24T, MH24TS, MH42TCopper ConstructionMilled brass fittingsPrevents unburned propane release 39in