This knob will ONLY fit BIG Buddy heaters with the serial number MHC748000097071 and LOWER.
This knob has a 12.5mm OD shaft size. Please measure outside diameter of knob shaft for proper fit.
For use on Mr. Heater, Heat Star, and Enerco older MH18B BIG Buddy Portable Propane Heaters.
(*Use Part #78418 knob for heaters with the serial number MHC748000097072 and HIGHER, and all CURRENT models, where the knob has a 27mm shaft base*.)