SINGER- Transparent Plastic Class Bobbins: Threaded. Fifty yards per bobbin of 100% spun polyester thread, size 50 and washable, colorfast. Use with Singer front load and top drop-in bobbin machines, Atlas, Brother, Domestic (rotary), Elna, Kenmore (rotary), Morse, Necchi, New Home (rotary/old style), Pfaff, Sewmore, Universal, White (rotary) and Wizard machines. This 3x6 inch package contains twelve threaded class 15 bobbins. Imported.