This single adapter is only compatible with the models that have an aluminium sub-platter.
See the advert with single adapter for Thorens TD 165 etc. for the models with a plastic sub-platter.
This single adapter holds the original Thorens mat in place. Next to this, it can be turned around to accommodate different sized records. One side bulges out to account for singles, and the other doesn’t bulge out to accommodate for full-sized 12-inch vinyls.
Warning: This is a plastic 3D printed product (the black product on the pictures), which is an exact copy of the original, aluminium adapter.