Garvin 52181-SPKR 4" Square Concrete Box w/ Mounting Tabs, 3-1/2" Deep, (4) 1/2" & (4) 3/4" Side Knockouts

4 in square 3-1/2 in deep junction boxes with mounting tabs and (4) 1/2 in & (4) 3/4 in side knockouts and a raised ground are used on concrete forms. Their external tabs allow installer to nail/screw boxes to forms for stability during pour. They are used when extra depth is needed for dimmers cameras speakers strobes signals and other electrical and electronic devices. Garvin' labor saving design eliminates the need to awkwardly install boxes and extension rings to accommodate deep devices.