Knockout masonry box
Measuring 3-1/2 inches deep and 3-3/4 inches long, the 1-inch KO masonry box is factory-made and features a one-inch knockout on each end and two on the bottom. It also includes two 1/2-inch and a 3/4-inch eccentric knockouts. The box is available in single-gang and is non-gangable. The masonry box offers a stable, welded steel, single-piece design for heavy-duty applications and will not deform after installation.
Thomas & Betts Corp.