RC20, complete strip of four, with the bottom stamp being a double transfer. This is one of the most dramatic 20th century double transfers, with doubling throughout the entire design: lettering, scrollwork, portrait, frame, and ornaments.
Below the strip, there is a high-resolution image of a normal stamp at left next to the double transfer at right. You'll want to double-click the image to view it at full size.
The DT stamp is a bit ragged at left, but still, neat to obtain as part of a complete strip.

