I recently embroidered some dark brown teddy bears, and the top thread kept pulling the bottom thread up. I kept thinking how I wish I had some markers that I could use to fill in where the Bobbin was coming up. Then I went on the sulky website looking for something else and ran across these markers. I bought them in an instant and immediately tried them out as soon as I got them. They work wonders! I can’t believe how well they cover up the bobbin thread. I just wish that it came with gray. As expensive as they are, I hope they last forever.