The Evoluent VerticalMouse 4 Right has a patented shape that supports your hand in a relaxed handshake position and eliminates the arm twisting required by ordinary mice. A fast adjustable 800 - 2600 dpi optical sensor reduces hand movements needed to move the pointer. The button force is light for easy clicking but still firm enough to avoid accidental actuation. 6 programmable buttons have 59 selectable functions each plus special features for scrolling and clicking to ease the workload.