Evoluent Vertical Mouse 4 (Small Wireless)Enjoy a more neutral hand position thanks to this vertical mouse that avoids forearm twisting. With a reshaped thumb rest to provide superior comfort and two thumb buttons for extended functionality, the Evoluent Vertical Mouse 4 (Small Wireless) is the best design yet. It features a thoughtfully constructed ergonomic shape with an extended lip along the bottom edge that prevents finger rubbing, and the pointer speed indicators along the thumb rest