Tacx, from NL uses nylon, and a sealed bearing , made in 10t [Campag] and 11t [Shimano]

they also are used for Rohloff's chain tensioners.. I got spare 10t from QBP, they distribute both
10/11..

I got some over the years, examples: Bullseye (were, red ano Al) some are silver/clear ano.
and one pair , Carmichael, used Ti. (and Al)

being old, hearing loss makes lots of stuff quieter ..