1/4"-20 Black Phosphate Grade 2 Lock Nuts LNS-410 (749 pcs.)

Diameter: 1/4"
Diameter 2: 1/2"
Thickness: 7/32"
Material: Steel
Finish: Black Phosphate
Driver Type: 7/16" Wrench
Thread Size: 20 (Coarse)
Hardness: Grade 2
Style: Top Lock|Type C
Type: Lock Nut

Box of 749.

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