Extend your outdoor round electrical box with this UL Listed, weatherproof, extension ring. Made from corrosion resistant, diecast aluminum alloy, its durable powdercoat finish, is designed to withstand the elements, any season, rain or shine. It's easy to install, and comes with an instruction card, gasket, 3 closure plugs and mounting screws. They have internal threads on their hubs that comply with NEMA requirements and accept most threaded fittings and conduits. They attach to 4" round weatherproof boxes when the installer needs added wiring capacity.
