the first time I saw one of these tools was back in 1992 or so. I was working at a fast food restaurant and some contractors came in to resurface all the stainless steel surfaces. They used one of these to "re-grain" the table tops.
fast forward five years or so and I watched a Delorean specialist use his "proprietary tool" to do the same on a car. I went "Hey! one of those things again!"
So when Eastwood introduced their amazing new invention, the SCT in the 2000's I recognized it instantly.
I’m not certain, but the oldest versions I’m aware of of this tool were either the German made FLEX version, or a version made by Makita.
I believe the two used different sized drums.
Fein made adapters for one of their angle polisher motors so the same type of drums could be used as on the FLEX version.
Walter Abrasives if I recall correctly, also made a version, but theirs used a different size of drum that might have been larger.
Festool’s “Protool” brand also I believe made a version, posibly using the same size of drums as the Walter version.
Suhner likely also sold a version.
The Makita version was mostly sold in the USA as a finishing version for brushing and stripping lumber, so I’m not sure whether you could get the same selection of drums for metal finishing.
All of the units were fairly expensive, with the Makira likely being the most affordable, although it still cost two or three times what the average common “professional” Makita power tool might cost.
The FLEX version was around $700+ for just the motor unit.
The German tool brand drums were usually $100-$200 each depending on the type.
This was back when a USA made Skil saw or Milwaukee top of the line USA made angle grinder might run $140.
Even a Festool track saw was half the price of the original burnishing tools, and that was before buying a selection of the drums.