Material The washer kit is made of high quality polypropylene, a plastic material with good insulating properties. The round washers are durable, easy to grip, and provide firm support. Size Each washer has a diameter of 1.77 inches and a center hole of 0.2 inches. They weigh approximately 1.7 grams each. The center hole is sized for easy fixing with screws of the corresponding size. Quantity The package includes 100 load spreading polypropylene washers, providing sufficient quantity for daily replacement and multiple projects. Function and compatibility These plastic flat washers are designed to distribute load and provide support when fixing rigid foam insulation boards. They are ideal for fixing insulation foam boards, expanded polystyrene boards, extruded polystyrene, and many kinds of foam boards. The 0.2 inch center hole allows easy fixing with screws of the corresponding size. Use scenarios - Installing rigid foam insulation boards on walls, ceilings, or other surfaces with screws that fit the 0.2 inch hole. - Fixing insulation boards to studs or frames to distribute load and reduce risk of foam board crushing. - Securing EPS or XPS boards in place during exterior or interior insulation projects and other foam board mounting tasks.