This item allows you to divide industrial serger thread and other threads by attaching it to the bobbin winding mechanism (bobbin winder) of a sewing machine. **Important Notes:** * When attaching to the sewing machine, align the spring on the shaft of the bobbin winding mechanism with the recess in the hole of this product (located behind the mark on the base surface of this product) until it clicks. * In the case of professional sewing machines or some home sewing machines, the shaft may be too thin, causing wobbling. * Wrapping masking tape around the shaft or inserting a piece of rubber band between the shaft and the hole may reduce wobbling and improve balance. * It is made to fit tightly to prevent wobbling. 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 by balancing it and tightening the nut. * 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, with approximately 20 uses. * Use a pen or similar to move the thread up and down to wind it evenly on the spool. * Thread, spools, bobbins, sewing machine, instruction manual, and sandpaper are not included. * May not be compatible with older home sewing machines that use thin plastic bobbins. * H-1 type metal bobbins have the same outer dimensions as the plastic bobbins compatible with this winder, so it will likely work with sewing machines for H-1 type metal bobbins. * May not be compatible with the latest sewing machines, old sewing machines, some professional sewing machines, and industrial sewing machines. * Secure industrial sewing machine thread by attaching it to a serger or placing it in a ceramic mug to feed the thread. * Use the bobbin winding mechanism effectively 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 may be burrs and printing marks characteristic of 3D printers. * Shipping costs are the responsibility of the seller. * It may take up to 6 days for delivery from the time of shipment. * Simple packaging using recycled materials such as empty boxes of confectionery.