The FW2 Kit is a 2lb Flat Washer Kit consisting of 6 different size flat washers. They areusedto increase the surface area of fasteners, in order to evenly distribute the force applied when tightening them to a surface. They are also used to prevent loosening due to vibration, to stop the bolt or screw from pulling through, and act as spacers. They are manufactured to the ASME B18.21.1 standard.