This is for a lot of 28 ( 12 have a lighter background & 16 have a green background) vintage circuit boards for scrap gold recovery. These are all the same style; they may have different model numbers, but as far as I can tell they are the same. I see lots of gold lines in the board; each board weighs 7 1/2oz. The total weight is 13 pounds. These have to layers of boards. each one has small boards plugged into the main board. The small boards have gold pins. The main board measures 6"X6" and has gold pins for a connection. I see two boards without a second layer; I took closeup pictures to show details. I took lots of pictures please see them closely for condition and details. Feel free to ask any questions. FREE SHIPPING ON THIS LOT!!!!!!!!!!!!