The NAS620 Flat Washer is a thin, circular disc with a hole in the center. It is made of 300 series stainless steel, which is a type of steel that is resistant to corrosion and rust. The washer is used to distribute the load of a fastener, such as a bolt or screw, over a larger area. This helps to prevent the fastener from pulling through the material it is being used to secure. The NAS620 Flat Washer is a DFAR compliant product, which means that it meets the requirements of the Defense Federal Acquisition Regulation Supplement.