O-Z/Gedney AX expansion fittings allow for expansion and contraction in a run of rigid metal conduit and IMC. They can be used for applications involving IMC. Due to the slightly smaller OD of the IMC a 15 in minimum length of rigid conduit should be used entering the expansion fitting. Type AX provides for a maximum of 4 in conduit movement, 2 in in either direction. Type AX-8 provides for a maximum of 8 in conduit movement, 4 in either direction.