Ed Z. asked me to check the table by the sound it makes when placing it on glass, but I didn't have any other metal mouthpieces to compare with and wasn't really sure. So I came up with my own test that is the same for any material or weight: 1. put several drops of water on the glass 2. push the table of the mpc down into the water (firmly) 3. lift the mpc straight up 4. if the glass doesn't lift too, you've got a bad table My Otto Link NY failed this, but both of my Vandoren rubber pieces passed with flying colors. It only tests the table area, but between this and the reed suction test (especially with softer reeds) you can get a pretty good indication with no special tools...