Bobbin Case Tension Gauge Towa Tm-3 Style M Jumbo Bobbin Case Japan Towa Bobbin Case Tension Gauge TM-3 For "M" Size Bobbins. For use with Style-M/Jumbo bobbins. The Towa bobbin tension gauge allows you to consistently set accurate bobbin tensions With the Towa Bobbin Case Tension Gauge the guess work is gone forever. This gauge allows embroiderers to consistently set accurate embroidery bobbin case tension In just a few seconds you can verify your bobbin tension is where it should be to achieve optimum results. It's simple to use and comes with complete instructions. No setup is required