"Amazingly, it did take roughly 1.2 inches or about 3 cm to move over 1024 pixels! As a comparison, I used my Logitech PS/2 mouse. In the end, my Logitech needed twice the length. That means the resolution of my Logitech is about 400 DPI. A quick test using Ken's Microsoft IntelliMouse Explorer USB produced the same results as my Logitech mouse."
FULL STORY @ ROJAKPOT (http://www.rojakpot.com/Reviews/XNTech_Play_Mouse_II/Play_Mouse_II_01.htm)