Tall bobbin, class 15

Taller versions of the class 15 bobbin. The standard class 15 height was 11.3mm. There are a few versions here - 13.3mm, 16.3mm, and 19.3mm. I tested the 16.3mm and the 19.3mm by winding them on a sewing machine from a serger thread spool, then using them on a serger in both loopers. The serger results were good. With some finesses, I guess a better winding job can be done on the 19.3. These can be used in the serger spools and coverstitch machine as well in place of the standard bobbins as the bobbins will run out of thread faster.