This is a generic module rack with eight modules installed, each with two vacuum tubes. The last module has no vacuum tubes present, and there are two unpopulated module slots. On the frame opposite the serial number the letter "J" is handwritten in grease pencil. There are a series of cooaxial connectors, with cut cables, running along both sides of the rack. They are numbered J1-1 through J10-4. At one end there are two terminal strips.