I bought these as a replacement for the factory felt pads for my Thomann FH 600 G Bb-Flügelhorn, as the stock ones were starting to make too much noise. They fit absolutely perfectly, quite tight in the inner ring, but then fits so snugly that no glue is required. Even though they are 3mm thick, they're actually a tiny bit thinner than the stock ones, so the damping is only a little better. But red looks nicer anyway :)