Kensington Expert Mouse The lower-left button (left-click by default) is not responding. I have confirmed that the other buttons are working. I have checked the trackball ring and it is working. There are some faded marks on the trackball. It is a USB wired connection. It has been used and shows considerable wear. There are also quite a few scratches and dust. Due to this condition, please consider it as junk. Would it be suitable for parts, etc.? Please check the detailed condition in the photos.