Thanks for the reply, I have read the link and was surprised to see so many some worn others not, no way are they some sort of caster they would just shatter or slip on stone floors, I liked the idea of being used with a sponge in the middle for stamps and maybe counting money, sorting through paperwork, the wear on mine would fit and I remember something very similar behind the reception desk at one of the hospitals I visit but plastic with a sponge in the middle also circular.