High quality materials: made of iron and galvanized. These butterfly shaped washers are sturdy, firm and not easily deformed. They are durable, resistant to wear and corrosion. Enjoy reliability and quality with these fixing washers. Seamless Application: When secured with the appropriate steel screws, our perforated thin metal washer adheres firmly to the surface. The perforation of the fixing disc allows the adhesive or plaster to bond to the surface of the board, minimizing the risk of delamination or surface damage. Used for insulation board, tile backing board, plaster board, composite board, extruded board, backing board on tiled floor or just for attaching building board to frames. Easy to use washers: These heavy duty fixing washers are suitable for installing tile panels. These fixing discs are designed to provide a secure method for fixing back panels and insulation boards to floors and walls made of common materials such as wood, concrete, thermoplastic panels and other construction materials. Package includes: Each pack contains 200 heavy duty steel washers, 28mm in diameter. Typically, 8 washers per plank are required, though this may vary depending on the size of the back panel.