ELECOM acquired FCC certification. Comes with both English and Japanese manuals Changing the common sense of index finger operated, index finger operated type USB trackball 'DEFT' With Back/Forward quick navigation buttons. Thumb-operated ball with advanced gaming sensor. For exceptionally smooth tracking Ball diameter size is 2.5mm. Ergonomic design of the thumb ball operation. Left/Right button made by OMRON With Back/Forward quick navigation buttons. With scroll Wheel. Resolution: 750/1500 count (switchable). It is easy to remove the ball, you could clean the hole easy. Simple package