The Bobbin 2518 Plastic is a Class 15 bobbin commonly used in various sewing machines. Bobbin Dimensions: Length: 20.38mm / Width Inside Diameter: 8.16mm / Height Diameter: 20.38mm / Center Inner Diameter: 6.1mm. Compatibility with Sewing Machine Models: 715, 730, 740E, B33, B35, B37, B38, Deco 330, Deco 340, Deco 340 Plus