Power inlet box by Generac Power Systems, Inc.

30A, Resin Power Inlet Box, Use A Power Inlet Box When You Need To Plug In Your Generator Outdoors To Connect To A Transfer Switch Indoors, Mount This Non- Metallic Power Inlet Box On The Exterior Of The House and Will Run Wire Through The Wall Over To The Transfer Switch, Rated At 30A For Generators Up To 8000W, NEMA 3R, Rated Non-Metallic Enclosure Is Made From Durable, Glass, Filled Nylon and Includes A 30A, 125/250V Male Inlet In NEMA Configuration L14, 30 On Bottom, Retains A Rain Tight Rating When Cord Is Connected, Required By Most Inspectors, Works With Any Transfer Switch Rated At 30A, Does Not Include A Flip Lid, UL Listed.