Hubble 50 amp 250 volts DC / 600 volts AC 3-pole (3-phase) 4-wire grounding non-NEMA power outlet in Crouse Hinds FD-2 cast iron condulet box with Hubble cast aluminum #7382 spring loaded cover. Box has one (1) 3/4" NPT hub. Cast iron box has two 1/4" mounting holes drilled on the back. Screw terminals on back. Grounding terminal on back.