Hi there histonetters - it's been a long time!!

Don't know if this will help but here goes:
Years ago we used something similar for cross matching blood in the blood
banks. They had weels and were made out of some sort of ceramic material -
glossy white like bathroom tiles - eventually white plastic (probably
cheaper) - try the blood bank/blood transfusion service - maybe you'll find
a member of 'the old school' who can remember!!
Good luck
Annie in Africa