Orbit Industries 4 in square boxes and extension rings are used in the installation of lighting fixtures, switches and receptacles. They are constructed from 16 ga galvanized steel. The 1-1/2 in D, welded boxes have multiple 1/2 and 3/4 in knockouts. Selected models include a bracket, such as the FB bracket for offset mounts on the sides of studs, the B bracket for face mounts or the AB brackets for side and face mounts. Non-bracketed boxes have a raised ground emboss.