There is a great book called "Featherweight 221, the perfect portable" by Nancy Johnson-Srebro. It will explain all about the slight changes ove the years, how to care for them and how to figure out how old your machine is. I have 3 featherweights, a black one from 1948, a white one from 1962 and a tan one from around 1963. There were not to many white and tan machines made. The book also tells you where they were manufactured, some in the US, Cananda and Scotland. There were even a few free arm machines made, would love to have one, to rare and expensive for my budget. It really interesting to see the machnes and the difference between them. Good luck if you buy one, you will not be sorry.