The spacing flat washer is made from extra-thick case-hardened low-carbon steel for surface strength and plated with black oxide for lubricity and corrosion resistance. The thicker material provides extra strength and load distribution. Washer has a round shape and suitable for use in general industrial, mechanical, machinery, and power transmission applications. The low-carbon steel is case hardened for increased surface strength. It is plated with black oxide for lubricity, which reduces friction generation. The coating also provides a mild corrosion resistance. The washer’s size corresponds to matching screw or bolt size. Washer is made in the USA. Washers have a variety of purposes. They can distribute the load of a threaded fastener and can also be used as spacers, springs, shims, and locking devices. Washers can be measured in inches or in millimeters, and typically have an outer diameter about twice as large as the inner diameter.