Hubbell - HBL2450Locking Devices, Twist Lock, Industrial, Single Flush Receptacle, 20A 3 Phase WYE 277 480 AC, 4 Pole 4 Wire Non Grounding, NEMA L19 20R, Screw Terminal, Nylon face, Back and side wire, Black Wire restraint recess for both back and side wiring, greatly reduces the possibility of loosening the terminal connection Face color coding by voltage facilitates locating and mating of proper devices All brass mounting and grounding system provides a lower