Well, I'll come back and state that I have more than enough bobbins --- most of my machines use the same class bobbins -- I've got a 328, 201-2, 403A which all use the same class of bobbins. And contrary to the experience some of you have reported, I've had no problems whatsoever with the Singer Class 66 Plastic Bobbins, so I have a plentiful supply. Unless it's a "Singer" brand, though, I would be sceptical about buying the plastic. I have quite a few FW Bobbins, the T & S Bobbins, so I guess I've collected quite a few of all the bobbins my machines need!
Jeanette