Rigid or IMC Conduit Threaded Aluminum Entrance Cap 2-1/2″
https://dev.nsiindustries.com/product/rigid-or-imc-conduit-threaded-aluminum-entrance-cap-2-1-2/
The Bridgeport 2-1/2″ Rigid or IMC Conduit Threaded Aluminum Entrance Cap serves as a connection point for service entrance wires. This threaded type entrance cap features one hole with 1″ dia, two holes with 7/8″ dia or three holes with 1-5/16″ dia.