Properties:

An item of metal and/or insulating material having a smooth interior with rounded edges to prevent damage to the insulation of the wire or cable emerging there-from, designed to fit through panel(s) or the wall of a junction box. It may be designed to snap into a knockout hole, or designed with an external thread and furnished with or without a locking nut. For items designed to couple conduit to junction box, see box connector, electrical. See also bushing, electrical conduit and bushing, nonmetallic. For items having hexagonal shoulders, see chase nipple, conduit.