This is one of at least 4 General Motors designs made in the late 1960s that feature a Lincoln head obverse. They were originally described as being made of 'powdered metal' but, according to Ken Potter, are actually made of bronze. Fewer than a dozen are confirmed. Additional information on these can be found in Pollock. A second Lincoln head design with a different reverse is also available for viewing. We are calling it P4056. According to Ken Potter, die varieties of this second design exist. Photo courtesy of Ken Potter.