Add a small momentary switch to your Commodore 64 Ultimate with this 3D printed support that goes into in the empty H-L hole in the back of the case. It's a non-destructive mod that can be reversed easily. I added some glue to hold it in place (not on the C64U itself to be clear). Note that the button may have to sit on a slight downward angle so as not to interfere with the top part of the case when closed. Just needs to be wried up to the GROUND and RIGHT pins on the "Button" header pins on the PCB.