Outdoor NEMA 3R power inlet box. May be installed outdoors up to 100 ft from a home's load center so your generator can be plugged in outside, away from open doors or windows. Designed to be hard-wired directly to Reliance transfer switches with building wire. Has four combination 1/2 in and 3/4 in knockouts (one on each side, bottom and back). 6 in height x 4 in width x 2.63 in depth. UL listed.