Outdoor NEMA 3R power inlet box. May be installed outdoors up to 100 feet 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" and 3/4" knockouts (one on each side, bottom and back). 6" height x 4"width x 2.63" depth. UL listed.