Janome front and side-loading machines require a separate bobbin case which also acts to control the bobbin tension. Although not generally recommended, more advanced sewists like to adjust the lower tension to accommodate special threads, such as when using a hand-wound bobbin of thicker decorative thread. You can avoid tricky tension adjustments afterward by having an extra bobbin case on hand specially adjusted for thicker or thinner threads.

Please note this bobbin case will only work with the machines listed