For use with single wire, nonmetallic wire 14-2 or 14-3, 12-2, or 12-3, or 10-2. Requires no tools, screws, or locknuts to assemble or disassemble. Durable plastic construction. Trade Size: 3/8 In., Knockout Size: 1/2 In. UPC coded. UL (Underwriter's Laboratories) listed.