EMT Or Rigid Screw-on Compression Coupling 3-1/2″, Zinc
https://nsiindustries.com/product/emt-or-rigid-screw-on-compression-coupling-3-1-2-zinc/
The Bridgeport 3-1/2″ Zinc Screw-on Compression Coupling ensures a secure, concrete tight connection between two lengths of EMT or rigid conduit. The coupling uses a screw-on compression fitting to keep the EMT conduit locked in place.