Excerpt: This is the replacement for the cordless optical trackball. They reduced the total number of buttons and for some odd reason, changed the ball position from the top, controlled by index/middle fingers, to the thumb. Who knows why but it takes getting used to and still doesn't work as well.they also reduced the number of programmable buttons.the only improvement is the receiver is better and smaller.bottom line - what the heck were they thinking?
Excerpt: This is my 2nd track ball like this. 1st one wore out after a few years so I purchased another just like it. From day one I had problems with the new one. The ball DOES glide smooth, but the pointer on the screen does not move with the ball. Going tonight to purchase a new one, different brand.