SINGER Class 15 Threaded Bobbins offer the convenience of 12 pre-threaded bobbins. The polyester thread comes in black and white. Each plastic bobbin has 50 yards of 100% spun polyester thread. Conveniently packaged in a see-through storage case. Bobbins are compatible with SINGER front load and top drop-in sewing machines. Consult your machine's manual to ensure correct bobbin size. Details: Black and white 50 yd. (45.72 m) each Set of 12 bobbins (6 white, 6 black) 100% spun polyester thread and plastic Includes reusable plastic storage case