5/16"-18 Grade 2 Zinc Nylon Insert Lock Nut - 60 Count 077116297723

Nylon lock nuts are hexagonal in shape used with bolts and washers of the same material, finish, and grade.
Features
Nylon insert prevents nut from loosening during vibration
The zinc coating provides a corrosion resistant finish
May be used as a secondary nut to help lock the main nut in place