56 Flat concrete adapter round ring is suitable to use with masonry box. It features 0.062-Inch steel construction and has pre-galvanized finish. It measures 4-1/2-Inch OD x 0.13-Inch. This adapter ring includes two retained screws. This adapter ring joins octagon extension ring to concrete ring. Adapter ring is UL listed, CSA certified and meets NEMA/ANSI standards.