Bobbin Saver 3 pack for Metal or Plastic Sewing Bobbins - Each can hold up to 30 Bobbins Each ring can hold up to 30 bobbins in plastic or metal. Keeps bobbin threads from unwinding or becoming tangeled. Made of flexable rubber for ease of use and durability. Bobbins will stay in place even turned upside down or dropped. 3 different colors to help identify different threads or machines.