Rigid or IMC Conduit Threaded Aluminum Entrance Cap 3/4″
https://nsiindustries.com/product/rigid-or-imc-conduit-threaded-aluminum-entrance-cap-3-4/
The Bridgeport 3/4″ Rigid or IMC Conduit Threaded Aluminum Entrance Cap serves as a connection point for service entrance wires. This threaded type entrance cap features two holes with 3/8″ diameter or three holes with 5/8″ diameter.