Are you struggling with tension? Do you find you wish there was a device you could place your bobbin case in and have it tell you if you need to loosen or tighten the bobbin tension so that you can focus just on the top tension? This is EXACTLY what you need. Using this bobbin case gauge couldn’t be more simple. Place the bobbin case in and pull on the bobbin thread. Then all you need to do is loosen or tighten the bobbin case screw so you can set the tension on a very low setting which will allow you to run even the finicky threads on your longarm!