The Conform Wrist Rest with SmartFit system enhances ergonomic positioning of your hand, wrist and arm for better support and more comfortable mouse use. Unique nonstick pads on the black base allow it to glide along a desktop with your mouse to provide continuous alignment that keeps your arm at a neutral angle. Conform padding material provides soft support, and the wrist rest helps reduce the risk of repetitive strain and carpal tunnel injuries. The included SmartFit size chart helps you find your personal comfort color (blue, red, green and yellow). To ensure a proper fit, simply switch out the four interchangeable SmartFit inserts in the wrist rest to use the one that matches your color. This wrist rest is compatible with all mice and ambidextrous for right-handed or left-handed use.