MIDWEST FASTENER Flat Washer, 5/16 in Dia Inside, 2.517 in Dia Outside, 0.083 in Thick, 2 Grade, Galvanized Steel, Package Type: Box, Package Quantity: 100.
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.