The Bobbinator is a patented device that allows a bobbin to be used as a top thread. Includes 10 DecoBob prewound bobbins. The Bobbinator increases storage and reduces thread wastage by turning your bobbins into a thread spool. Sew economically: no need to purchase a separate top thread for small to medium sized projects. The Bobbinator can be used on horizontal and vertical spool pins. It also keeps bobbin threads clean, organized and prevents thread from unspooling. Includes a reserve compartment to keep 3 additional bobbins in storage, fits a total of 4 bobbins.