http://www.ismacs.net/singer_sewing_...ine-manual.pdf
I found a manual that can be downloaded and has the explanation on the attachment feet. Ismac has all sorts of Singer manuals for free if anyone needs them. I have both the 301 and 301A but haven't used them much or even cleaned them up. My husband fines more then I can get done or else I am on the website too much. It must be he fines more then I can get done! Hope someone can use this site as I believe it is a very good one.