This is a fully tested and functional Laboratory Counter purchased in an auction at Ohio University. I can't find a serial number on it (I think it is too old for that), but the only other items I could find online that looked identical had the serial number 41566106, so I am assuming it is from the same batch, and I included it in case someone was looking them up by serial number. You push the button-levers to increase the numbers above them, and every time you push any of them the number on the right increases. You turn the knobs on the ends to reset the machine. I read that it is used for counting blood cells, but I can't verify that for a fact. Great for a lab, or just for an interested person to add to their collection. Good luck and happy bidding!