2-1/8" deep, 4" square welded boxes with (6) 1/2" & (6) 1/2"-3/4" Side Knockouts and (2) 1/2" & (2) 3/4" Bottom Knockouts are installed in walls or ceilings for lighting fixtures, switches, receptacles or other outlet devices. Square boxes are used to bring power to a number of electrical devices where multiple conductor runs are split in two or more directions. Garvin Industries’ 4S Boxes can be surface- or flush mounted when multi directional conduit runs are necessary.