Thomas & Betts XD6-TB 2 INCH EXP/DEFL COUPLING

A plain expansion coupling only takes up movement along the length of the conduit. The XD6-TB is an expansion/deflection type, so it handles axial movement plus angular deflection and side-to-side offset at the joint. That is what you want at a building separation, seismic joint, or bridge/parking deck joint where the two structures move in more than one direction. If your run only grows and shrinks with temperature in a straight line, a straight expansion fitting is the simpler choice.

Ductile cast iron. That is the load-bearing body of the fitting, which is why these get specified on exposed structural joints and in areas where a conduit fitting can take a knock rather than in light interior work.

At the point where the structure itself moves, not mid-span. On a rigid conduit run crossing a building expansion joint, seismic joint, or between two separately supported structures, the XD6-TB goes directly at that joint so the movement is taken by the fitting instead of the conduit or the boxes on either side. Support the conduit on both sides of the coupling so the fitting is free to move.

Order by the XD number, not the trade size alone. The 2 inch is XD6-TB. When you spec it, confirm the conduit trade size at the joint and the amount of movement the structural joint is designed for, since those two things drive which fitting in the XD line you need.