Rainmaker, I have a Handi-quilter machine and have used the prewound L bobbins. When I first got my machine bought a box of bobbins from a shop and the lady said they would work for my machine, so I used them. Several boxes later I realized that they were L and that M is what I needed. So...I use filtec bobbins, both sizes (L for my smaller machines, M for LA) and order by the box. The centers are identical, if you save them and send back when you reorder, they give you credit for them. The only difference is the amount of thread wound on the bobbins. If still not sure, call Handi-Quilter to reconfirm. Just my opinion.Peace, Brenda