I've got a telescoping 3A post in good shape.
I used it on a "running rig" I had for a long time and now, I'm getting rid of all the parts.
It is fine and has about 10 inches of telescoping.
There are holes at the top and bottom to allow cables to be run up the post.
The bottom fits into a dovetail and allows you to adjust it back and forth.
No idea of value.
Buyer pays insurance and shipping.
Use the e-mail address listed below.