Square Cover. Plaster Ring, Mud Ring | 4 11/16 in Square, 2 in Raised Single Device Tile Cover | 4 in Octagon Back Plate With 3/8 in Fixture Stud; (2) 1/2 and (2) 3/4 in Knockouts | Use Through Knockout to Connect Box to Conduit Coupling; Use With a Locknut to Connect Two Boxes Side by Side or Back to Back; Use With a Locknut to Connect Fixture Housings in Continuous Runs; Rigid Conduit Threads (Nps)Furbay Electric Supp