Set Screw Coupling, 6″, Malleable Iron for a Concrete-Tight Fit
https://dev.nsiindustries.com/product/set-screw-coupling-6-malleable-iron-for-a-concrete-tight-fit/
The Bridgeport 6″ Concrete-Tight Malleable Iron Set Screw Coupling joins two unthreaded rigid or IMC conduits for a long-lasting fit.