3/8"-24 18-8 Stainless Steel Fine Thread Nylon Insert Lock Nuts (12 pcs.)

Diameter: 3/8"
Diameter 2: 21/32"
Thickness: 15/32"
Material: Stainless Steel
Driver Type: 9/16" Wrench
Thread Size: 24 (Fine)
Hardness: 18-8
Style: Waxed Nylon Insert
Type: Lock Nut

Box of 12.

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