The Singer Bobbins Bundle includes 36 threaded bobbins as well as a set of three bobbin rings. The three bobbin sets are class 15J, and each set contains twelve bobbins in assorted colors, providing a total of 1,800 yards of bobbin thread. Each set comes in its own case, which is made of clear plastic for easily picking out the color thread needed, and the cases have snap-tight latches to keep contents secure. The bundle also includes a set of bobbin rings for easy organization. The bobbin rings measure 3” in diameter and are constructed from durable nickel-plated steel. Each ring opens easily, snaps securely closed, and can hold 16-18 bobbins per ring to conveniently transport thread bobbins, add to a sew kit, or hang on a peg near the sewing machine for easy, visible access. No more searching through a drawer or sewing kit full of loose bobbins and other sewing machine accessories to find the right color or thread weight for your sewing project. With this bobbin and storage bundle, your thread bobbins will stay neat, organized, and easily accessible for your next machine sewing project.