For all home sewing machines using Size "L" bobbin. * Eliminates backlash & bird"s nests on the underside of your quilt! * Easy to use! Just drop Bobbin Genie into the bobbin case. Replace bobbin and insert into the machine. * Long lasting! Super slippery, tough and durable! Designed by: Sharon Schamber * Use during free-motion quilting, thread painting or embroidery when changing directions at high speed.