This is the best trackball ever produced other than the trackball explorer. It uses rollers for the trackball points so the points will never wear flat, but still uses a pure optical sensor like a tbe. I've modified mine with a trackball from a trackball optical which is much smoother than the speckled ball that comes with it. I've also modified mine to extend the side keys out, because of it's smallesh design it's buttons aren't in a natural position and can be a bit straining on the hand after a while. Once those simple mods are done it's equal to a tbe or better. They're extremely extremely rare. Good luck finding one.
