Diameter: #6Diameter 2: 3/8Thickness: 1/32Material: Stainless SteelHardness: 316Nominal Size: #6Type: Flat WasherBox of 50.A flat washer is a thin, usually round, plate with a hole in the middle that is normally used to distribute the load of a threaded fastener. USS flat washers have a large, wider body. SAE flat washers are machined to a tighter specification and have a smaller outside diameter.