I've added my review to the original thread after testing this for a few months....
McMaster-Carr ½” Grommet (item 9600K22 )
A buddy gave me some to try and I was hooked. They’re taller, fatter, and weight more than other “O” ring damps and remarkably flexible. That squishiness coupled with being gummy (not sticky though) grips the strings so well.
I don’t understand why this one works so well but it’s now on all my racquets. Although only crazy people use more than one, I've experimented quite a bit using 1 to 5 at once. For some reason using 3 seems to feel best. Just put me in the looney bin.