Kinematics were (allegedly) made in Wickliffe, OH, where my father had grown up. It's near Cleveland.
I have a couple I found on ebay fairly cheap. I'm gearing up for 4x5, but so far have not yet found a Super Speed Graphic in my price range.
Thus, I've not used them yet, but have cycled them quite a bit.

They are decently made, though not as well made or solid as the Grafmatics. As with the Grafmatics, make sure the septa are straight and true.

Unless you can test it before purchasing, assume it will be well-used (in rough shape) and either pass or don't spend too much. If you can test it, cycle it a lot. Go through the ten septa many times, as a jam may not occur reliably.

One of mine jams periodically, and it seems the issue is with a little wear and misalignment of the counting mechanism. I worked out how to disassemble it, and believe I can make it reliable without too much effort. The mechanism seems simple enough that if nothing is actually broken or greatly worn, it should be fixable.

Information is difficult to find online, but is there. Sorry, I didn't save the links I'd found. From what I've read, they tend to jam more than Grafmatics, but with service and care should be fairly reliable. Service is the tricky part; I've found no information on that. When I rebuild it I will have to figure it out as I go along.