Intertherm Flue Extensions And Accessories Roof Jack Cap. Before purchasing make sure your old crown can be removed. Fits Miller Intertherm Nordyne and Broan furnace model numbers starting with MI MBHA MGBA MGBB MGHA MGHB MMBA MMBB MMHA MMHB MSBA MSBB MSHA and MSHB. Features of Intertherm 903656 Flue Extensions And Accessories Roof Jack Cap Redesigned all-weather crown assembly Helps minimize pilot light blow-outs Fits Miller Intertherm Nordyne and Broan furnace models Model Numbers: MI MBHA MGBA MGBB MGHA MGHB MMBA MMBB MMHA MMHB MSBA MSBB MSHA and MSHB Package Contents: Intertherm 903656 Flue Extensions And Accessories Roof Jack Cap Intertherm 903656: Flue Extensions And Accessories Roof Jack Cap