Two Screw Strap Type MC Connector 1-1/2″, Die Cast Zinc Round
https://dev.nsiindustries.com/product/two-screw-strap-type-mc-connector-1-1-2-die-cast-zinc-round/
Use Bridgeport’s two screw strap type connector to connect interlocked metal clad cable to an electrical box or enclosure. This connector comes with a round opening for installation into the knockout.