Funny, I was having trouble with my sewing/embroidery machine skipping stitches. I tired everything. The tech told me to use a metal bobbin instead of a plastic one. No more skipped stitches! It is a drop in bobbin. Unless the machine has a special made plastic bobbin, he said use a metal one in all of my machines. I trust him. He has performed miracles on problem machines that others gave up on.