With the Simplicity Portable Sidewinder, you will no longer have to unthread your sewing machine to wind your bobbins! This is a portable, battery operated, no-fuss innovation that will allow you to efficiently prepare for your sewing projects. This product does not require a sewing machine, auto-stops when your bobbin is full, comes with 2 x AA batteries and suits A or L style bobbins. With compact dimensions of 14.5 cm x 9.5 cm x 8 cm, the Simplicity Portable Sidewinder can easily be stored away.