Dear Steve, In my experience there are very few Flexshaft systems
that have different shaped shafts. And it is the shaft that dictates
the type of hand piece that can be used. For instance, the Foredom H
series has a square shaft and will only work with hand pieces the
have the "H" designation in their description. All others, that I
have seen, have a round shaft with a "fin" at the receiving end of
the shaft. This fin fits into the hand piece and is what drives it
(the hand piece). Please keep in mind there are a lot of products
similar to Foredom so I could be off but I doubt it.
Now, all this being written, it's harder to match the off brand inner
shaft to the motor than to a hand piece, so when you purchase an off
brand flexshaft do your homework on replacement parts.
I hope this helps.
Rio Grande Technical Support 1-800-545-6566