I'm doing what we all are, clearing out unused stuff.
Here are some monitor arms.
They are for the PRO 1 or 2 post, 1.5" if I have it right.
Some are just hybrids that I used for making a Frankenstein rig or was trying out various LCD rigs and they just have the 1/4-20" screws on the end.
One is clearly a McMaster collar and a bunch of parts. (It does work but you'll have to figure out the details on your monitor.)
One is an single piece monitor arm from a 3A or PRO 1, its got the spud for accepting the TB-6 monitor and others of its vintage.
These things were always the hardest things to come by back in the day but now we're all just searching for good deals on stuff.
Make me an offer and you pay shipping.
don't leave messages on the forum, sometimes hard to get to.