I received a used ATX PC case and it was missing the stock USB and audio ports. There is a great supply of aftermarket boards on eBay, but the one i received did not match the standard spacing I found on 2 different PC cases, so I made a simple cover. The outer holes are intended for screws to mount to the case. I found that the USB ports have enough tolerance that makes fitting one of these covers tricky, so I've opted to for more clearance. I'd recommend a few dabs of hot glue on the rear of the cover for security.