Yes, it is very important that the bobbin is correct. I have an older Bernette and the bobbins look just like my old Singer bobbins, but they won't work in the Bernette. I had a terrible time sewing and finally took it in and found out that I had to buy Bernina bobbins. I always make sure I have the correct bobbin for the sewing machine, I don't like seeing all those loops in the bobbin thread or having threads break over and over. Easier to get the correct bobbins first.