First Means of Securement For Heavy Duty Box Bracket, Provides Securement For MC/AC And EMT Conduit, Works With Heavy Duty Rigid Box Support And Heavy Duty Telescoping Bracket, Snaps Into Channel And Locks Into Place Without Screws, Rigid Locking Tab Securely Locks Into Place When Closed And Opens For Easy Conduit Placement, For Use With 4-Inch Boxes, 3/4-Inch EMT Conduit & 14-2 to 12-3 MC Cable (All Sold Separately)