The Classic Trackball is the Classic with an integrated 25mm trackball conveniently located in the upper right corner of the keyboard. The Classic Trackball is a good solution for space constrained work environments.
The Classic Trackball is available in Pearl White or Raven Black(with gray keys); available in USB or PS/2 interfaces; and available with buckling spring or rubberdome switch technology. Rubberdome versions can be found on the Quiet Touch R/D page. You can also specify many other versions using the Keyboard Configuration Tool.