Locking Devices, Industrial, Male Plug, 50A 3-Phase Delta 250V AC, 3-Pole 4-Wire Grounding, Non-NEMA, Screw Terminal, Heavy Duty Black- Super tough nylon housing offers better impact qualities- Stainless steel shroud protects contacts and prevents mismating- Box terminal with hex socket threaded slug, permits high clamping pressure on conductors without damaging strands- Thermoplastic polyester interior provides heat resistance and impact strength Super tough nylon housing offers better impact qualities Stainless steel shroud protects contacts and prevents mismating Box terminal with hex socket threaded slug, permits high clamping pressure on conductors without damaging strands Thermoplastic polyester interior provides heat resistance and impact strength