3/8" x 45/64" Zinc Plated Grade 2 Steel External Tooth Lock Washers

Diameter: 3/8"
Diameter 2: 45/64"
Thickness: 5/64"
Material: Steel
Finish: Zinc
Hardness: Grade 2
Nominal Size: 3/8"
Style: External Tooth
Type: Lock Washer
Application: Round|pan|or binding head

Box of 36.

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