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.

Diameter: 7/16"
Diameter 2: 1-1/32"
Thickness: 5/64"
Material: Steel
Finish: Hot Dip Galvanized
Thread Type: USS
Hardness: Grade 2
Nominal Size: 3/8"
Type: Flat Washer

Diameter: 9/16"
Diameter 2: 1-3/8"
Thickness: 7/64"
Material: Steel
Finish: Hot Dip Galvanized
Thread Type: USS
Hardness: Grade 2
Nominal Size: 1/2"
Type: Flat Washer

Diameter: 3/8"
Diameter 2: 7/8"
Thickness: 5/64"
Material: Steel
Finish: Hot Dip Galvanized
Thread Type: USS
Hardness: Grade 2
Nominal Size: 5/16"
Type: Flat Washer