Square Head Close-Up Plug | Control Circuits Lighting Ballasts Meter Circuits Electronic Circuits | Designed to Compensate for Length Changes Due to Temperature Variations in Exposed Conduit Runs | Electrical Distribution | For Reducing Conduit Entries to a Smaller Size in Threaded Rigid and Imc Conduit Systems | For Use in Metal Framing Applications | For Use With Threaded Rigid Metal Conduit and Imc | Use Through Knockout to Connect Box to Conduit Coupling, Use With Locknut to Connect Two Boxes Side by SideFurbay Electric Supp