Nylon Insert Lock Nuts have a nylon insert. These lock nuts offer excellent vibration resistance. The nylon collar prevents liquid seepage and internal corrosion. Compressive forces grip on the bolt and prevent loosening. Nuts may be reused. Zinc plated fasteners have good corrosion resistant qualities and are a good choice for indoor, outdoor, and industrial applications. Grade 2 is regular strength for everyday use. Grade 5 nuts are used for critical joints and high stress applications.