1/2"-20 18-8 Stainless Steel Fine Thread Nylon Insert Lock Nuts (6 pcs.)

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

Box of 6.

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