EMT Compression Connector 3-1/2″, Zinc Plated Steel
https://nsiindustries.com/product/emt-compression-connector-3-1-2-zinc-plated-steel/
Use Bridgeport EMT compression connectors to connect electrical metallic tubing to an electrical box or enclosure. Compression type EMT connectors are quick to install and create a concrete-tight seal at the point of connection.