Symmetrical base with easy gliding - Allows the user to rest both hands comfortably next to the vertical structure promoting the use of the larger muscles in the front and upper arm to manoeuvre the mouse. Fine cursor control is still accessible with small hand and/or finger movements. The penguin marks a major breakthrough in the fight against health problems that occur when computer users spend too much time with a conventional mouse. It sets new protection standards against a number of diseases of the upper extremities such as injuries caused by repeated strain (RSI) and carpal tunnel syndrome (CTS) and left hand allows you to divide the workload and avoid exaggerated movements of the wrist that can increase pressure on the soft tissues in the carpal tunnel. Regular changing of hands during the day prevents static muscle tension (SMS) in the arm and shoulder - a main cause of discomfort during mouse work. The penguin mouse is also antimicrobial to inhibit the growth of bacteria. This makes it perfect for hot desking environments. The penguin mouse is available in three sizes. To choose the right one for you measure your hand from the first fold on your wrist to the tip of your middle finger. Small 0-16 cm (approx. 0-6 inches)Medium 16-18 cm (approx. 6-7 inches) large 18 cm + (7 inches + approx.).