while shopping in JoAnn I was looking at bobbins and noticed there are a number of different sizes. They are marked by the term "class" But this page has almost any kind you could want, if you knew what you needed.
http://www.sew4less.com/category/2/Bobbin
Just look at all the sizes and varieties! Is it any wonder we get confused and purchase the wrong bobbins? For a long time I thought bobbins were all one standard size, then I began to find out some of the more expensive machines had their own special bobbins. Nothing is standard anymore.
Get out that manual and see if you have some notations on what size to buy, both bobbins and needles.
Happy quilting, girls.
June