1/4"-20 Zinc Grade 8 Nylon Insert Lock Nuts (16 pcs.)

Diameter: 1/4"
Diameter 2: 1/2"
Thickness: 21/64"
Material: Steel
Finish: Yellow Zinc
Driver Type: 7/16" Wrench
Thread Size: 20 (Coarse)
Hardness: Grade 8
Style: Nylon Insert
Type: Lock Nut

Box of 16.

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