This secure black/white locking plug from Hubbell Wiring Device-Kellems will keep your equipment from disconnecting. This locking plug has a L21-30P configuration with a voltage of 120/208VAC and an amperage of 30. It has 4 poles and 5 wires. This locking plug has a for flat cable. It has 3 phases. It is made of nylon material. This has a grade of industrial. Standards include: UL/CSA.