7 types of hexagonal screws with internal and external teeth Practical Furniture Accessories: Hexagon screws with internal and external teeth are suitable for soft woods such as pine, plywood and fiberboard. Ideal for furniture combinations, especially wooden furniture. High Quality Material: The built-in nut is made of high quality zinc alloy, which is hard, durable, dimensionally stable, resistant to wear and corrosion. Easy to install: Just use an Allen wrench to drill and tighten the zinc alloy nut.The thread design provides good tensile strength and effectively prevents tearing due to twisting or vibrations. Various sizes: Allen screws include M4 * 10 30 pieces M5 * 10 30 M6 * 10 20 pieces M6 * 15 15 pieces M8 * 15 10 pieces M8 * 20 8 M10 * 25 7 pieces 7 sizes can meet your different needs. Packaging: Comes with 120 pieces of Zinc Alloy Furniture Hex Socket Screw Inserts in 7 sizes including plastic boxes for easy storage and sorting.