1/4"-20 18-8 Stainless Steel Coarse Thread Serrated Lock Nuts

Diameter: 1/4"
Diameter 2: 1/2"
Thickness: 1/4"
Material: Stainless Steel
Driver Type: 7/16" Wrench
Thread Size: 20 (Coarse)
Hardness: 18-8
Style: Serrated
Type: Lock Nut
Diameter 3: 19/32"

Box of 10.

A lock nut is a nut that resists loosening under vibrations and torque.