Diameter: 3/4Diameter 2: 1-3/4Thickness: 3/32Material: Stainless SteelHardness: 316Type: Flat WasherBox of 2.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.