These brand new, high quality aluminum bobbins will fit most industrial sewing machines such as Emel, Jocky, Two Lion, Bright etc.
Aluminum bobbins are considered the top-end "Luxury Bobbins" because they add much less resistance or drag to the bobbin thread tension and is ideal for difficult or problem applications.
Aluminum is usually machined to higher tolerances than steel and are recommended by Sewing Machine Manufacturers for Machines with thread undertrimmers.