Miriam, Have you noticed that some of the vintage Singer low shank attachments are a little taller than others? I have, and thought at first they were the high shank attachments, but don't think that Singer made high shank attachments. I do have some newer Sears high shank attachments and they are a lot longer than the others. I'm wondering if there wasn't so much 'quality control' on the height of some of the low shank attachments. Or could it be that some Singers had the presser foot bars at different lengths for the low shank? Any one know???