Very well studied

You use it, it works. No driver to download.
It is to replace a Logitech trackball that after two years was double clicks without being asked her.
It appears (see previous comments) that would be more reliable Kensington ... we'll see.
The scroll baque around the ball is soft and handy. Contrary to some opinions, we do not confuse with the ball, except when used with a boxing glove.