Sigma's Conduit Locknuts are used for securing Rigid conduit, IMC and other threaded connectors to a steel outlet box or metal enclosure. These locknuts are of zinc-plated steel construction. Secures Rigid conduit, IMC and other threaded connectors to a box or enclosureCompatible with 3-in Rigid conduit, IMC and other threaded connectorsZinc-plated steel construction