I have a Viking with a drop in bobbin, so the Bobbin case is not the the typical and stays in the machine when changing bobbins. I can take mine out and there is a tiny adjustment screw for tension. I ended up purchasing a seperate one for bobbin work, it takes more effort than a regular bobbin case to remove . I have also used the regular bobbin case when I use narrow ribbon and by passed the traditional threading, sending the ribbon up thru the needle hole ( by passing all of the tensions) manually and taking a few stitches with the wheel to anchor the first few millimeters, once that is done the upper thread and feed dogs will keep it moving. Hope this helps.