The 221 can be any of several different featherweights, the black ones, the white ones, the tan etc. The 222 (see picture) is the free arm one that was made to be used England (220 power) in the early 1950s right after they were still trying to recover from loss of manufactured goods from WWII. They are noteworthy because they can lower the feed dogs as well. Only about 9,000 were made and so it is one of the rarest. The very rarest version was the black crinkle style make during WWII for the military use. They wanted one that was not shiny.