never heard of, is it a new digital? to you have a booklet? they usually will say the size. I have several Kenmores and they all use this size, it is a more universal size, that you will see in the notions isle.
still won't let me reply. No its an older model made by singer, 1987. the book says class 66. I mistakenly bought class 15 but they don't work. Funny though both sizes measure the same.
well these are not flat when you lay them on a table, the edges round to the inside very very slight, you cant even measure it. My machine takes both flat and round, its the total width that matters.