The USB receiver is missing. Therefore, I cannot confirm its operation, and I'm selling it as junk. I used it about 5 times. I lost the receiver and couldn't use it, so I stored it at home for a while. This is only the main unit and case of the Elecom wireless trackball "M-MT1DR" series. There are no issues with the ball movement. The case has scratches. Please refer to the images for other minor scratches.