When sewing, pre-wound bobbins may save a lot of time. It's wonderful to be able to jump right in without having to wind bobbins beforehand or stop in the middle of a project to wind more. Furthermore, pre-wound bobbins usually retain more thread than bobbins wound on your machine.
Remove the side papers on each end of the prewound bobbin when using a paper-sided prewound bobbin. When using prewound bobbins with a central core, the bobbin thread sensor does not operate. Prewound bobbins should be wound in the same direction as ordinary bobbins.