Reversible locknut designed to cut through protective coatings on boxes and enclosures to ensure ground continuityFlex conduit/bx connectors 90 degree - indoor only bag size 3/8 inches Zinc die cast. In a dry location, use to connect flexible metallic conduit (Greenfield or BX) to a steel outlet box or other metal enclosure. 3/8 inches size fits 1/2 inches knock outs.