1. Double functions: for threading, it helps pass thread through the needle eye easily, especially useful in low visibility or poor lighting conditions; for inserting, it securely holds needles to prevent them from falling during needle changes. 2. How to use: for threading, first insert the thread into the V-groove of the threader; next, position the V-groove over the needle just above the needle eye; then, slide the threader down the needle while gently pushing until the threader pin enters the needle eye. 3. Durable material: this needle threading tool set is made of quality plastic and metal, offering durability and long-lasting performance. 4. Wide range of usage: compatible with various household sewing machines that lack automatic threading functions, including many older sewing machine models. 5. Common dimension: the sewing needle inserters are approximately 7.5 cm (3 inches) in length and 1 cm (0.4 inch) in diameter, a standard size designed for comfortable and convenient handling.