Class 15 Bobbin Metal - Recirculated
Class 15 is a style of bobbin that started with the Singer 15-XX line of machines in the early 20th century. They have become a common style of bobbin for many front or side load machines with metal bobbin cases. Come in multiple varieties, some with and some without holes, etc..
There is no such thing as a universal bobbin. Pleases make sure you are getting the correct style for your machine. If in doubt, ask us and we will help you.