$1 1935-A Silver Cert, Fr. 1610 Red S EXPERIMENTAL Great Look! PMG Ch Abt Unc 58

In 1944 the Bureau of Engraving and Printing decided to experiment with a new paper for silver certificates. Some 1935-A silver certificates were marked with a red R to designate the regular paper; others were marked with a red S to signify that they were printed on special paper. Thanks to their attempt, we now have terrific collectibles! 

This example has been preserved well with exceptional eye-appeal!