The Cantex 18 cubic inch rectangle PVC 1-gang electrical box is built for both new and old work applications. Made from Schedule 40 durable non-conductive PVC, it will never rust or corrode, making it ideal for demanding environments. UL listed and UL Marine listed, it conforms to NEMA TC-3 and UL514 standards. With 22.5 cu. in. of surface mount capacity and approval for use in concrete, this gray box delivers long-lasting performance and code compliance for residential and commercial electrical installations.