This NESCO RBK575S is a durable, weatherproof round outlet box constructed from cast aluminum. It comes complete with a cover and gasket, making it ready for installation. Designed for electrical device mounting, it features a 3/4 inch hub size and is suitable for outdoor use.The NESCO RBK575S is a 3/4 inch round outlet box made of cast aluminum. It includes a cover and gasket and is rated for outdoor use. The box features a 3/4 inch hub size and a round shape.