Fractional currency shield

A fractional currency shield is a 20 in × 25 in printed "shield" on which were placed images of 39 different fractional currency notes. Produced in 1866 and 1867 by the United States Treasury Department, the shields were sold to banks for $4.50 each, for the purpose of having images of genuine notes available for use in detecting counterfeits. The 39 notes were printed from the original plates on one side only, the other side left blank, or with the printed word "specimen".

This keyword could refer to multiple things. Here are some suggestions: