All of these units are clean, spin freely and without vibrations (at normal speeds silly). They all have high quality feet and/or fresh feet added by me which don't degrade easily like a ton of other lab equipment.
I have serviced them all by doing the following:
1) inspecting the hardened bearing on the bottom that the turntable pivots on. If it was missing I pressed a new one into the bottom
2) verified all of the feet are present and level, replacing them if they were not all present
3) checking the turntable shaft for marring or damage where it pivots, buffing the bottom lightly with a fiber wheel where applicable so it freely spins
4) wiping the shafts down from debris and adding a very light weight oil to help with spinning and to prevent rust.
5) verified all of the tables have clearance over the feet. If the parts wear out and the table drops too low it will rub on the top of the feet and vibrate. It turns very poorly in that case, so I just took the feet/pedestal and turned down the top of the foot pedestal to make clearance for the turntable so it will spin freely.
The listing is for 1 piece. There are various models present, but they're effectively all the same.
If you ask nicely I can make you a bent glass rod out of 5mm or 7mm borosilicate to accommodate the turntable. This isn't included unless you ask. You can either message me ahead of time or include it in the message/note when making a purchase.
Let me know if you have any questions by selecting "message seller" next to my username on eBay.
Thanks!