The most commonly used accessory for working on a laptop or computer is still the mouse. A good, ergonomic mouse is therefore essential. The Evoluent 4 is a so-called vertical mouse. You grip such a mouse in a hand-shaking position. In this position, the wrist bends less sideways and the forearm has to turn less. If you... use the wrong mouse, this can lead to pain and problems in your shoulders, forearms and hands. With a vertical mouse, you prevent many of these problems.