Borden Milk advertising clock

20" across has a metal black back with wear signs like it has hung for years. I bought this clock from the estate of a friend who passed away who collected advertising memorabilia for years. I don't know where he bought it from but always admired it. I have never seen another one and cannot find any information on this clock. it is a spinner clock. There is no name on the back and I don't want to take it apart.