I put my bobbins into cases. One case is labeled for my 2662 and the other is labeled for my 401. I used to use the rubber band idea but then I would need the spool of thread for one machine but not the other and it just works easier. Not so confusing and not rolling all over the place. DH was looking for a bobbin to change the other evening and he liked the idea of being able to go right to the case intended. He even filled a couple that had emptied out.