I don’t think they make them anymore… I’m fairly sure I had the same one you’re talking about (slight oval shape, button on the back), I lost it a few days ago (I didn’t put it on right) and when I went to get another one there weren’t any there, not even on the website. They only had the $60+ which serve the same purpose for 3x the cost. :(
Why did you have to look? Now the magic that keeps it all together has been dispelled. :(