World’s First Mouse with Grooved ButtonsYour fingertips rest in a shallow groove on the buttons. This patented innovation secures the mouse in your hands and makes moving it much more precise.Avoids Forearm Twisting For ComfortThe ergonomic shape supports your hand in a handshake position. Since 2002, users continue to report that Evoluent VerticalMouse provides superior comfort and even relieves their wrist pain.