About 3 or 4 lifetimes ago, during the big CB fad, I built a stub matching SWR system. After playing with it for awhile, I put it in a box and I've been storing it now in my shed for about about 30 years. Everytime I look at it, I get tempted to throw it in the garbage, but somehow, I can't bring myself to just throwing it away. So, I am willing to give it away or sell it for the best offer (USA addresses only).
If memory serves the system consisted of a whole bunch of RG-8 coax pieces with connectors on both ends that range from probably 1/4 wave length to just a few inches. It also includes some tees and maybe some adapters and it includes a home-made box that I used to use that can be connected to the tee for dialing in a variable capacitance or inductance. I would guess the box probably can't take a lot of power. I might also have a CB SWR meter in there also.
The way that I used to use it was to attach an extender cable to the transmission end of the coax then I would insert a "T" and connect the box and dial it back and forth until I got a match. Then I would record the L or C value and look at a chart I used to have and construct a coax stub that would provide the same reactance.
I would guess the best use for this would be for someone who is building a switchable antenna array, for example.