Zinc plated locking nuts have a special nylon insert.
These nuts have been designed to remain secure despite severe vibration.
Having a nylon insert makes the nut better at sealing the bolt thread against leaking water, oil and other liquids.
When you insert the mating bolt into the nylon insert, the thread from the bolt compresses the nylon.
Features and Benefits
Greater resistance to vibrations and torque
Mild steel grade 8.8
Retains locking ability up to 250°C
Resistant to organic acids, solvent, oil and mineral salt