Genuine 78018 Red Safety Knob used on Mr. Heater MH18B Buddy Heaters. For Mr.Heater, Heat Star and ENERCO MH18B Big Buddy Heaters with 12.5mm OD shaft stem OD. Part # 78018. 12.5mm Base OD. Use The 78418 knob for older style with the 27mm shaft base.
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