It's a controller designed by Mark Kelly. There were only a few of us who built them. They were a pretty complex and aggressive DIY project. Mark didn't want to support the myriad of questions that came out of the build - his build notes and board layout and adjustment descriptions were not precise enough on their own and the extra time he needed to spend supporting it was excessive.
However the end result, once working properly and adjusted correctly is awesome. A motor spinning in your hand outside of the casing is effectively vibrationless; truly smooth and almost feels like it isn't even turned on.