Diameter: 3/16"
Diameter 2: 11/32"
Thickness: 1/32"
Material: Steel
Finish: Zinc
Hardness: Grade 2
Nominal Size: 3/16" (#10)
Style: Safety
Type: Lock Washer

Box of 30.

The purpose for a lock washer is to prevent threaded fasteners from loosening by creating friction between the fastener and the mounting surface.