Style "L" aluminum bobbins provide more consistent tension with a variety of bobbin threads, from cotton to polyester to specialty threads. Shipped with all new machines, these are light weight, greatly reducing bobbin thread backlash. These bobbins fit APQS machines equipped with "Smart Bobbin" technology.
Style "M" aluminum bobbins are light weight, reducing bobbin thread backlash. Aluminum bobbins help provide more consistent tension by reducing inertia as the bobbin spins. These bobbins fit APQS machines equipped with the "Big Bobbin".