Starting in 1928, the United States began issuing its currency in a reduced size format. People were using new-fangled "wallets," and the large size notes just didn't fit in them well. Small size notes came with many different colored seals and serial numbers, each reflecting a different type of issue: Silver Certificates were blue, Gold Certificates were gold, and Legal Tender Notes were red.
In addition, Federal Reserve Notes (green) and National Currency (brown) filled out the spectrum. Collectors have begun to realize how scarce nice condition small size notes are, and have been eagerly buying them up. With the recent changes in the designs of our paper currency, the earlier notes are all disappearing.
#207430: 2 Digit Serial Number ..... oooooo75 from the BA Block.
#129811: Super Low 3 digit Serial Number. ooooo830.
#126147: Super Low 3 Digit Serial #., ooooo938.
#126146: Super low 3 digit serial #., ooooo356.
#136085: Philadelphia District. PMG notes "Good Embossing".