I can say that the one I own, and am selling on this site, works perfectly...
I used it with a Sonus (think Mayware) Formula IV unipivot arm, where I think it's probably most at home (it's one that you often hear is best for such arms), although it worked just as good on my father's RB300.
I used it with a Sonus (think Mayware) Formula IV unipivot arm, where I think it's probably most at home (it's one that you often hear is best for such arms), although it worked just as good on my father's RB300.