Square Head Close-Up Plug | Control and Motor | Control Circuits Lighting Ballasts Meter Circuits Electronic Circuits | Designed to Compensate for Length Changes Due to Temperature Variations in Exposed Conduit Runs | Dusk to Dawn Lighting Control | For Use With Threaded Rigid Metal Conduit and Imc | Lighting Loads/ Branch Circuit Loads | To Connect Threaded Metal Conduit to a Threadless Opening in a Box or Enclosure | Use Through Knockout to Connect Box to Conduit Coupling, Use With Locknut to Connect Two Boxes Side by SideFurbay Electric Supp