Sold in sets of 10 bobbins same size.

Bobbins come in three sizes.

4″ bobbins fit the 9″ mini, the 11″ shuttles, and both double-bobbin boat shuttles;

5″ bobbins fit the 13″ shuttles; and the 6″ bobbins fit the 15″ shuttles.

The bobbins have specially designed ends for trouble-free release of yarn.