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