This can be attached to the bobbin winding (lower thread winding) mechanism of a sewing machine to divide industrial serger thread, etc. **Important Notes:** * When attaching to the sewing machine, align the spring on the shaft of the lower thread winding mechanism with the recess in the hole of this product (located behind the mark on the surface of the base of this product) until it clicks. * In the case of professional sewing machines or some household sewing machines, the shaft may be too thin, causing wobble. * Wrapping masking tape around the shaft or inserting a piece of rubber band between the shaft and the hole may reduce wobble and improve balance. * It is made to fit tightly to prevent wobble. While it has been confirmed to work with several sewing machines, if it is too tight, carefully widen the hole with sandpaper wrapped around a chopstick. * A recess has been provided on the bottom so that it can be used with some professional sewing machines such as JUKI Spur. * Secure the thread spool with a nut to balance it. * Over-tightening the nut may cause damage. * Use it safely at low speeds, less than 60 revolutions per minute. * High-speed rotation may cause it to break and fly off, which is dangerous. * Materials: Base = Polylactic acid (PLA), Screw = Stainless steel, Decorative nut = PLA * Estimated lifespan is 3 years, and the number of uses is about 20 times. * Use a pen, etc., to move the thread up and down to wind it evenly on the spool. * Thread, thread spools, bobbins, sewing machine, instruction manual, and sandpaper are not included. * May not be usable with old household sewing machines that use thin plastic bobbins. * H-1 type metal bobbins have the same outer shape as the plastic bobbins compatible with this winder, so it will probably work with H-1 type metal bobbin sewing machines. * May not be usable with the latest sewing machines, old sewing machines, some professional sewing machines, and industrial sewing machines. * Attach industrial sewing machine thread to the serger or fix it in a ceramic mug, etc., to supply the thread. * Use the lower thread winding mechanism skillfully or apply appropriate tension with a "sub-tension" device to prevent loose winding. * Receipts are not issued. * Weight: Approximately 20g per piece * Length of the screw protruding from the base: Approximately 8.7 cm * There are burrs and printing marks unique to 3D printers. * Shipping costs are borne by the seller. * It may take up to 6 days for delivery from the time of shipment. * Simple packaging using recycled materials such as empty confectionery boxes.