Use the blank cover to cover up an old vacuum hole in the sheet rock or to gain access into a wall. It is referred to as part number SV8012 in the VacPan instructions. The dimensions are 4-3/4" tall by three inches wide. Screw holes on center are 3-7/8" apart from each other at 12 and 6 o'clock. These covers WILL NOT SEAL the backing plate lowering the suction of the vacuum system, only an inlet wall plate will seal the system. Three covers come in one package.