Did they change the look of the class 15 bobbin sat some point. The ones I have look a little different to the ones I just looked at on line. And the ones I just looked at - look exactly like the A156 bobbins. The new ones that came with the machine are flat on the ends but the ones I had for the old machine are flat but has a little dip or ridge around the edge - not sure how to explain it better. The ones for the old machine are Dritz bobbins. Think I answered my question - looks like I need to order some new bobbins Class 15 and not Dritz - those weren't rated too good. Any opions would help.