Shake hands with your mouse. Fully-featured mouse with scroll wheel, left, right, forward, back. Low battery indicator. Natural handshake position improves wrist posture for better comfort. Contoured, natural (46.7 degree) slope keeps the wrist in a neutral, eliminating soft tissue compression. An extended lip for the little finger provides complete support for smoother, larger muscle group movement. USB connection. Uses 1 "AA" battery (included). Medium. Grey.