These professional and practical nuts are made of carbon steel material with galvanized technique, making them last longer. With high hardness, they are not easy to break or deform, suitable for most fixing work like license plates, drying racks, installing air conditioners, fixing pendants in containers, adjusting things, to meet your needs. Features - Color: silver. - Material: Carbon steel galvanized. - Size: 2.50X1.40X1.40cm/ 0.98X0.55X0.55inch. - Note: Suitable for 0-5mm thickness between the steel sheet, use 10mm drill hole to drill, opening diameter 21mm. - Using carbon steel materials with galvanized technique, are safe, . - Strong and efficient with the high hardness, easy to use by the simple structure. - Spiral thread, the force is uniform, and the rotation is not easy to skid, safer for using. - Suitable for most fixing work like license plates, installing air conditioners, fixing pendants in containers and more. - Fast installation with manual or pneumatic tools, don't over tighten or you may strip the thread. Operation procedure: 1. Drill to the recommended diameter. 2. Tap the anchor into the hole until it is flush with the surface of the substrate. 3. Attach the installation tool to the screw head. Squeeze to expand the anchor. (Small size can be set with a screwdriver) 4. Remove the screw and through the fixture and place back in the anchor. Tighten the screws until the fixture is secure. Package list: 15 x Expansion Nuts with Screws(M5x25)