Head YOUTEK IG Prestige Mid Plus Grommet is available from TW.
Post #2 is semi-true. All Prestige 18x20 MP (98 in²) are compatible. Problem is not all the newer Prestiges are 18x20 [not talkig about the Prestige Pro]. They went to 16 mains, etc making them no longer able to use the older grommets.