CST2145W (L-Trac) USB Wired High Performance Trackball (Beige) - Made in the USA Width 3.75" (9.5cm), Length 6.75" (17.1cm), Height 1.75" (5cm) Ball Size: 2.25" Model ID # CST2145W Made in the USA Resolution: User selectable 400, 800, or 1600 counts per inch