If you can help I.D. Manufacturer of this clamp I'd appreciate it, another taper here has asked about I.D. and source, it's been too long to remember, no paperwork on our end.
That's a Rowi clamp. I have several models and like them very much. The top portion in your photo with the rotating ball head can unscrew out from the clamp and extend similar to the 2nd link below. Search ebay for "Rowi clamp". There are many available.
Here's one on ebay:
https://www.ebay.com/itm/137183901682
Different model showing the extension capability:
https://www.ebay.com/itm/127873144836