This 4 sq-in, 2-1/8 in D, cut-in wall box allows installers to add devices, speakers, strobes, alarms and many other components to existing hollow walls. The 4 sq-in in hole mounting provision in fits many common electrical and electronic devices and rings. 1/2 in and 3/4 in conduit knockouts on the sides and back of the box allows bi-directional conduit and cable attachment. Medium 2-1/8 in depth is great for most wall thicknesses constructed of standard framing materials. This old work box comes complete with attached plaster ears to catch the wall surface when used with snap-on old work clips that secure it tightly to drywall, tile or plaster.