A: I used a plastic Bloem Tahoe pot & it works well. It says 7" on it, but the top rim measures 7 1/2 inches. It tapers down so the top extends over the ring & it doesn't slide through. My ring is 5 3/8 on the interior diameter. The ring sits about 2 inches down on the pot.
A: Hi. I measured the inside of the metal circle at 6". I have a plastic pot that looks like a clay one, and it is one of those that is bigger at the top/opening--it has a rim. Since my pot seems to be a hair under 7" in diameter in the opening, it fits fine. So if your pot tapers and has a rim of ~7" and a body of ~ 6", then it will fit (the rim will keep it from sliding through. Does that help?