The 3M Ergonomic mouse is clinically proven to alleviate pain and discomfort of repetitive stress injuries in the hand, wrist or arm associated with the use of traditional mice - which can pronate the forearm and wrist and typically presses the wrist and carpal tunnel area against the desk. The vertical grip design keeps your hand and wrist at a neutral angle, while the mouse works as a regular optical mouse. Grip the handle and rest your hand on the base. Use your thumb to left and right click.