What you get: the package includes 4 pieces sewing machine bobbin case, you can change and replace according to your own interest, or share with others Application: the bobbin case is always applied as a replacement part for sewing machines with front-loading bobbin systems, it can also be applied as a spare case Function: bobbins can stop spinning more quickly, effectively preventing unraveling or tangling of bobbin thread when sewing operations stop and start Size: each bobbin case measures approx. 22.75 mm in diameter, can use for most sewing machine, such as applying for Babylock, Bernina, Brother, Elna, Janome, Kenmore, Singer and more Material: the bobbin case is made of stainless steel, that is durable and very practical, can serve for long time usage