A simple trackball is a pointing device with a ball that contains sensors which helps in detecting the rotation of the actual ball. An optical trackball on the other hand is different from the normal trackball. These optical trackballs use very tough state Optical Navigation Technology in the place of traditional mechanical assembly of conventional trackballs. The only movable part in the whole assembly is actually the ball, whose movement is sensed without the need of encoders and separate shafts. For more details visit, https://www.seatronx.com/rugged-products/tsx50-industrial-waterproof-panel-mount-trackball/