PREMIUM Bobbins - 36 pcs muti-color Prefilled Prewound Bobbins Thread as a pack Bobbin size: Size A, Class 15, can be applied for a variety of sewing machines . Perfect for anyone just starting out with a sewing machine. Material - Bobbins are made of stainless steel, durable, sturdy and can be used for a long time. Can be easily wrap the line on it without breaking. MUTI-COLOR BOBBINS: There are 36 bobbins which twined the 36different colors threads(Each color 1bobbins) and these bobbins also can be used to new bobbins after the threads were finished. KEEP THE BOBBINS ORGANIZED: Comes with a clear transparent bobbin case，Plastic made with clear view is easy to see which color to choose and let your hand sewing in an orderly way. REUSABLE PREMIUM Bobbins - 36 pcs muti-color Prefilled Prewound Bobbins Thread as a pack