Organize your sewing threads neatly with the Dritz Class 15 Reusable Bobbins. This pack contains four (4) Class 15 bobbins that are designed to fit in machines such as Singer, Baby Lock, Riccar, Simplicity and White. Always consult your sewing manual to determine the proper type of bobbin needed for your machine, and use only the same type (plastic or metal) of bobbin that came with your machine.