Suzanne,
The Singer Improved Family or early Class 15 are still available new. I believe Cindy Peters @ Stitches In Time still keeps them. The are very tiny bobbins.
Our W&W style mystery bobbins appear to be the same thing.
https://www.facebook.com/17308731937...type=3&theater
Jon
Last edited by jlhmnj; 12-08-2015 at 02:38 PM.