^^^^
that probably covers it.
(just finished typing..haven't followed link)
It's a folding small floor-fill light stand base with a thumb-scew tightened socket that secures a vertical stanchion. I bought it as a set with a short 2' single-telescoping Bogen extension that extends 14" or so. That extension is what I usually use for this, but is not what you see in the photo above. This time I used a cusom bar I made a few years ago specifically to hold the big TLs as close to coincident and to the center of the tube as possible. It was made to screw onto the stud at the top of a stand with a nut welded on the bottom, but the outside diameter of the tubing also fits perfecty into this foot socket, so it also works great low, on-stage. There is a threaded stud at the top which the Tetramic is attached to.
The foot may be availible alone, I know the extention is. It is simple, very stable, and folds up like a hand fan. Drawbacks are that it is a bit heavy since it is all thick steel, that the legs sometimes stick out a bit far for some situations, and that minimum hight with the Bogen extension is about what you see above with the custom bar. Not as heavy as a weighted base, though.
edit-
Thanks Flipp, I forgot I blathered extensively about that already!