You have to be careful when buying "featherweight" bobbins on eBay. I bought some; although they look identical to real 221 bobbins, they do not work. I loaded one up and tried to sew but couldn't make a single stitch. Upon closer examination, the bobbin extended past the bobbin case ever so slightly...not more than 1/32 inch. Then I switched to the original bobbin that came with my machine and it sewed perfectly. Since then, I found some more original bobbins.