Bridgeport 1257-S 2-1/2 IN Serv. Entr. Cap Set Scr, Box of 1
https://nsiindustries.com/product/rigid-or-imc-conduit-set-screw-aluminum-entrance-cap-2-1-2/
The Bridgeport 2-1/2″ Rigid or IMC Conduit Set Screw Aluminum Entrance Cap serves as a connection point for service entrance wires. This threaded type entrance cap features one 1″ dia hole, three 7/8″ dia holes or three 1-5/16″ dia holes.