This Jumbo Metal Bobbin holds 40% more thread than traditional L sized bobbins. More thread on the bobbin allows you to keep embroidering longer without interruption. Keep a few on hand so that you can wind a new bobbin using the independent bobbin winder on the machine so that you always have a full back up on hand for when you do finally run out.

This is for the HD9 Version 1 only, you can find the your version number on serial plate on the back of the machine.
Note: the MB-4S and the MB-7 take the next generation of bobbins, V2!