I to ma ru Bobbin Thread Tangling Prevention Tool (10 Pieces) It is easy to store bobbins that are easily entangled with threads.  Since it removes it from the sewing machine and installs it on the spot, work efficiency improves.  Because it is a simple structure it is hard to break.  It can be used for most bobbins to attach to the flange.  Hold the flange tightly and it will not come off even if it falls from a height of 1 m.