Crouse-Hinds Concrete box is suitable to use with 4-Inch octagon steel speciality box. It features steel construction. It measures 4-Inch x 4-Inch x 2-1/2-Inch. Octagon concrete box with two knockouts, includes 1/2-Inch and 3/4-Inch single row knockouts. It has 29-Cubic-Inch capacity. Concrete box is UL listed and CSA certified.