This is a regular dies trial piece struck in copper from Breen's 2-B | Bass/Dannreuther-2 die combination. It is believed to be a true die trial as opposed to being something deliberately struck for sale to a collector.
The coin is unique and is ex Newcomer, Raymond 2/42, Farouk, Bolt-Stacks 4/66, Paxman-Bowers and Ruddy 11/74, Stacks 7/08. As one can see from the image, the coin is cirulated and slightly bent.
Photo courtesy of Andy Lustig.