Six 1/2" and 3 TKO conduit knockouts (sides). Three 1/2" and 2 TKO conduit knockouts (bottom). Combination cover screw heads provide for faster mudring/cover installation. FM bracket mounts flat on side of stud and provides a rigid, secure box installation. Square boxes are installed in ceiling or walls for lighting fixture or receptacles. 4" square x 1-1/2" deep - 21.0 cubic inches. UPC bar code. UL Listed.