The one I got with Kurzweil PC3K8 broke its spring on its 4th year of usage. I really needed a new one. I tried with some cheaper brands but wasn't satisfied, so I got this one keeping my fingers crossed. Well, it was a great investment. I really just hope it doesn't break like the last one, but the chances are pretty low based on its rigidity and strong build.
Perfect for Kurzweil product. No polarity issues whatsoever.