EMT Or Rigid Screw-on Compression Coupling 4″, Zinc
https://testing.nsiindustries.com/product/emt-or-rigid-screw-on-compression-coupling-4-zinc/
The Bridgeport 4″ 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.