I had the smaller Simplicity bobbin winder which handles more than one kind of bobbin...Class 15 bobbins, Viking bobbins, etc. I did not like it because the bobbin would stop winding before it got filled up all the way. I just bought the Simplcity Deluxe model...haven't tried it yet...hope to do that tomorrow (Tuesday). I have several prewound size L bobbins which I can stil use on my DSM. Still, it will be neat to rewind those bobbins onto Class 15 for my Bailey. Besides, these bobbins are already paid for, lol.