Flat-topped and bottomed design ensures smooth fabric feeding for consistent stitching
Standard 20.3 mm diameter and 11.7 mm width fits most modern sewing machines
Plastic construction offers lightweight durability for everyday use
Security notch prevents accidental removal during operation
Summarized by Shop
Class 15 bobbins are standard, flat-topped, and bottomed bobbins (approximately 20.3mm diameter, 11.7mm width) commonly used in modern home sewing machines with drop-in cases, including brands like Bernina, Bernette, Brother, Singer, Babylock, and Janome. They are available in metal or plastic, often featuring a security notch.