Singer Bobbins Class 15 Transparent, 4-Count Set of 4 Class 15 transparent bobbins Compatible with select SINGER, Atlas, Brother, Domestic, Elna, Kenmore, Morse, necchi, New Home Pfaff, Sewmore, Universal, White, and Wizard machines Made of plastic for durability Never add thread to a partially wound bobbin as it may be uneven and cause thread to tangle or break