6 PCS. Bobbin Case for a Consew 206RB GAMMILL SEIKO .
A special anti-spin spring is built into the bobbin case assembly to prevent the bobbin from spinningwhen the machine is suddenly stopped. If the bobbin spins when the machine stops, there is a good chance that a single loop of thread will fall out of the bobbin case. This condition will cause the thread to snap as soon as the operator begins to sew.