#10 x 3/16" x 21/64" Polished 18-8 Stainless Steel Lock Washers (20 pcs.)

Diameter: 3/16"
Diameter 2: 21/64"
Thickness: 3/64"
Material: Stainless Steel
Finish: Polished
Hardness: 18-8
Nominal Size: #10
Style: Medium Split
Type: Lock Washer

Box of 20.

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