Hubbell - HBL7764CLocking Devices, Twist Lock, Industrial, Female Insulgrip Connector Body, 50A 250V DC 600V AC, 3 Pole 4 Wire Grounding, Non NEMA, Screw Terminal, Nylon housing thermoplastic polyester interior, Black Box terminal with hex socket threaded slug, permits high clamping pressure on conductors without damaging strands Heavy duty two piece external cord clamp provides maximum strain relief Box terminal with hex socket threaded slug, permits high clamping