7/16"-20 18-8 Stainless Nylon Insert Lock Nuts LNSS-167 (8 pcs.)

Diameter: 7/16"
Diameter 2: 23/32"
Thickness: 15/32"
Material: Stainless Steel
Driver Type: 5/8" Wrench
Thread Size: 20 (Fine)
Hardness: 18-8
Style: Waxed Nylon Insert
Type: Lock Nut

Box of 8.

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