The Vertical Mouse 4 (Right handed ergonomic mouse) by Evoluent helps avoids forearm twisting for comfort and good health. The shape is thoughtfully sculpted for uncompromised comfort and easy-to-reach programmable buttons. No finger contortions are needed to operate the buttons. The thumb rest has been reshaped to provide even more comfort over earlier versions. Now featuring two thumb buttons, a new bottom thumb button provides greatly extended functionality when used with the included driver. An extra wide lip along the bottom edge prevents the last finger from rubbing the desk. Pointer speed controls on the side allow convenient adjustment