You peaked my interest.

https://www.aimtools.co.uk/collectio...nt=32001335498

Similar, but a little cheaper (for a set of 4).

My own experience of using (non-castor) levelling rubber feet on a myford ML7 on an original stand (which makes it somewhat top-heavy) is that you can get a bit of swing going with too soft a foot. If these are a solid nylon foot, and onto a flat surface then this is likely to be alleviated somewhat.

... which has got me thinking of replacing the feet on the lathe - the area behind it into the corner has become a bit of a store and being able to move the lathe has some appeal.