I originally bought this thinking it was designed for existing construction. It is not, but you can easily make it work for this purpose. Using a hack saw I simply cut off the tab portion on the screw side so it goes flush against the stud. Then I put two screws into the stud through the side of the plastic frame, and it snugly fit the wall. If you cut the sheetrock the right size, it's a seamless installation and works quite well. Cut the sheetrock the exact dimensions of the frame and it can go in diagonally for positioning. I'm using these with the 2-Gang Recessed Low Voltage Cable Wall Plate (4001) for an in-wall cable solution.
PROS: Item is exactly as described and allowed me to help ensure a great looking home theater wiring installation. We are in the process of finishing our basement and I ordered a LOT of miscellaneous parts from Monoprice, including this item. Monoprice can't be beat on price and service. Everything arrived quickly and professionally packed. I am really eager for this project to finish so I can hook everything up and enjoy all of the components I purchased from Monoprice!