SINGER Class 15 Threaded Bobbins offer the convenience of 12 pre-threaded bobbins. The polyester thread comes in a range of colors, including navy, white, black, gray and red. 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 bobbin sewing machines, along with Atlas, Brother, Domestic (rotary), Elna, Kenmore (rotary), Morse, Necchi, New Home (rotary/old style), Pfaff, Sew More, Universal, White (rotary) and Wizard sewing machines.