Replacement thermocouple for Original Series Mr. Heater Tank Tops model No. F273100, F273105, F273200, F273300, F273305, F273600, F273605, and F273900. Prevents unburned propane release. Copper construction with milled brass fittings. No. F273117: Length: 12-1/2"", Model Number Compatibility: Orig Series Mr. Heater Tank Top Models