A box of 100 countersunk washers designed for use with NoMorePly insulated XPS backing boards. With a 35mm diameter and multiple fixing points, the circular washers can be used for bridging between two or more sheets onto both walls and floors. These premium stainless steel washers are designed for securely fixing boards to timber, preventing screws from dipping into the boards and compromising their integrity. Crafted from high-quality stainless steel, these CSK washers are both robust and easy to use. Their round shape and optimal size of 35mm make them versatile for various insulation board applications. These washers promise longevity and performance in every use. They are suitable for bathrooms, wet rooms and more. * Designed for use with XPS insulation boards * High quality for a strong and more reliable fixing * Prevents screw heads pulling through the boards * Stainless steel for durability and corrosion resistance