Optical Ergonomic Mouse Unique vertical grip keeps hand and arm in a neutral position, reduces pressure on wrists median nerve. Clinically proven to reduce discomfort associated with carpal tunnel syndrome. With programmable third button. For Windows® 95, 98, NT 4.0 and Mac®. USB and PS/2 connectivity. Small/Medium Graphite WEIGHT: 1.5 lbs. SOLD AS: Each STOCK NUMBER: EM500GPS