I bought these wanting as low profile rings as possible. For an 11mm rail I naturally can't find as low profile as for a 20mm rail. These ones also sit slightly higher than advertised. More like 14mm instead of 12mm so that's a shame. Still, they are pretty good quality for the price. Happy with them overall.
Caroma 300111 Pedigree Toilet Seat Rubber Buffers
28 July 2020
Expensive but necessary
As others have mentioned, these are relatively very expensive compared to the cost of the full assembly and surprisingly hard to find elsewhere. They are, however, good quality and exactly what I needed.