Mobile Home Parts. Roof Jack Cap Assembly. Fits Miller, Nordyne, Intertherm Roof Jack Cap Assembly Fits Miller, Intertherm, Nordyne & Broan Furnace with model #'s that start with MI, MBHA, MGBA, MGBB, MGHA, MGHB, MMBA, MMBB, MMHA, MMHB, MSBA, MSBB, MSHA & MSHB. Factory Replacement item...........Not a Generic! Roof Jacks & Caps are no longer made for furnaces with MHA & MAC model #'s Redesigned all-weather crown assembly helps minimize pilot light blow-outs!!! Outside pipe is 8-3/4" which fits over an 8-1/2" pipe on the furnace. Inside pipe is 5-5/8" which fits over a 5-3/8" pipe on the furnace. Easy Installation Instruction included!!!