This mouse uses a ball to rotate two slit disks placed in the X and Y axis. The slit disks are placed between a set of light source and optical sensor. Any rotation of the disk causes a the slits to cut the beam of light received by the sensor which is translated into changes in the respective axis. Any movement of the ball is thus translated into changes in the X and Y axis. Mechanical mice are on the way out due to the advantages offered by the equally priced optical mice.