As far as I can see they are a variant of the wet tumbler cleaners albeit an expensive version.
You would get the same results with a normal rotary wet tumbler.
I have one of these (got it some time ago when it was a lot cheaper!)
https://1967spud.com/extreme-rebel-1...r-220-volt-kit

And a mate has one of these. And is very happy with it
https://www.amazon.co.uk/BestEquip-P...ps%2C71&sr=8-3

ATB
James