Turnlok Plug 4wire 30amp 3phase 480v | Quick-thread assembly screws and cord-grip screws come backed-out, ready-to-wire. | Industrial-strength, brass alloy plug blades and connector contacts resist heat rise, provide excellent conductivity. | Raised ribs provide non-slip gripping profile for turning to lock and unlock. | Double dovetail design provides superior protection against cord pull-out forces. | Impact- and corrosion-resistant durable nylon 6 shell material. | Rounded back contour reduces snags and hang-ups on the job site. | Scallop shell design provides non-slip gripping surface for insertion and withdrawal. | Visible stamped NEMA configuration and device rating. | New-design external cord grips provide visible assurance of safe and proper cord retention. | Integral flexible rubber cord grommet conforms to and seals around SO cord to provide protection from oils, water, or chips entering wiring chamber.