Shallow, slightly domed, plastic bobbin for older drop in, top-loading, Singer machines. 10.8mm high. This bobbin is for your inherited mammie’s or auntie’s heavy old Singer machine (hand-crank or electric), built anytime between about 1930 and 1980. It won’t fit the new Serenade or Tradition-type models with a front-loading bobbin case. For newer, front-loading machines, buy the universal 15K bobbin instead.