This is a regular dies trial piece, struck in brass, of the 1908 St. Gaudens design with the With Motto reverse used from 1908-1933. These are listed in Appendix A in earlier editions of Judd.
These were flattened by being passed through rollers removing most of the design details except for the edge device which is still sharp on these.
About a half dozen are known including the illustrated example and 4 others offered as lot 5189 of the 1998 ANA sale.
Photo courtesy of American Numismatic Rarities.