This is the kit for building the system bus display. This display is not part of the computer itself. That is, the computer will operate by itself without this display attached. However, when the bus display is attached, and the computer is run with the slow clock, the activity on the system buses can be followed. It allows you to see how the microcomputer system works. If the activity is a little fast even with the slow clock, you can take a video of the display and go frame-by-frame, and see what happens on the buses with each clock cycle. It is one of the educational features of this computer kit project.