I have the Towa bobbin tension gauge and the Top tension gauge.I don't use the top tension gauge so much.But I do use the bobbin one a lot.When you buy one or the other ,superior has video's you can watch on your computer., and you get a paper telling you what tension you should be at.If you don't have that paper you can print it out from superior.Just put in what kind of Machine you have and print it out. P.S don't care for top tension gauge...