When I bought the DRO kit for my milling machine, I only bought scales for the X and Y axis, as the mill came with its own "built in" Z axis DRO. I have found out since that although the small Z axis digital scale on the front of my mill works very well, it is almost impossible to see clearly. Partly because of the adjacent window and partly because of my shop lighting. Since I have finished all of my project work for the moment, I decided now would be a good time to address this issue. I need a very small, easy to mount light that can shine light onto the dro and not in my eyes. I found an add for 12 volt lighted license plate bolts during a google search, and these seemed to be about perfect in size and mounting capability. My lighted license plate bolts arrived today. Aren't they cute little devils. I haven't tried them on a battery yet to see how bright they are, but the size is perfect for what I want to do. Tomorrow I will go over to Sayal Electronics and chase down a 12 volt dc output wall-wart and a small switch.