I cannot find any information on this gauge, except Chicago. I thought Million was the manufacturer, but maybe it's related to the measurements. I welcome a message from an Ebayer who knows about this. Model VV AC & DC Ohm meter. Mount diameter is 2-3/4 (housing OD) and face is 4-5/8 x 4-1/4 inches. Untested. Plastic-type housing. If not used for testing, think about your next industrial project, rat rod car project, or office and bar decor!