Maybe someone here in RCM has seen or used this lathe accessory.
I saw one of these a while ago on eBay, and was unable to locate any info about it then, and when I spotted another one with the accessories and operating instructions recently, with only minutes left in the auction, I bid on it kind of impulsively just because I wanted to see it up close.
All I've been able to locate by Goog searches have been patent website references, or results for a belt device bt Dynabrade.I suspect that this may have been a short-lived amazing new product that never really caught on, maybe from the '80s or '90s. There is no motor, so it may have been intended as a cheaper alternative to a toolpost grinder. If you've priced new toolpost grinders, you know how much they can cost, but I don't know how much this lathe kit sold for.
It resembles the old style of pivoting knurling accessory which had two knurls arranged vertically in a pivoting head.
It's very similar to that style, but with grinding (or polishing) wheels in the head assembly. The wheels are geared to each other, and friction against the rotating workpiece drives the wheels. Instead of the wheels just rotating with the workpiece like set of knurls would, the gears drive the grinding wheels in opposite directions.
If anyone knows anything about these Superfinishers, I'd enjoy hearing about them.