Wall Electrical Box Blank Plate - Extremely Flat

This is a cover for a US standard "single" wall box. In my case, the box holds past-use audio and video cables. I want to hang items on that wall without the old plate getting in the way.

I needed a very flat blank plate that I could paint over so that it would be much more hidden than the standard thicker (5mm thick) plate. The thinnest design that I came up with is 0.5mm thick.

Per the Home Depot website, my design is a replacement for the thicker "1-Gang Midway Blank Nylon Wall Plate