One mouthstick for mouse funtions, the other for over 48 funtional choices on keyboard & mouse. Each mouthstick has sip & puff, & 4 way directional operation. Software gives cursor control from very fine, to very fast. Little to no head movement needed. Software can do ANYthing on keyboard and mouse,(short of typing) including multimedia controls (ie: Ctrl-Z,or open internet,or open favorites, with one sip). Mounts to this 'Loc-Line' support arm in any position, with '3M' 'dual lock' pads. [See other album here for support arm info] [Current build cost approx $120, software $10] [Software available at Xpadder.com] [For Mac use see USBoverdrive.com, $20][MouseOnAStickInfo@gmail.com] Support arm is additional cost. FYI.. some commercial mouses available for special needs: http://tetramouse.com/compare.html , as a comparison.