Permatex Threadlockers are superior to conventional lock washers, nylon inserts and other mechanical devices because they secure the entire fastener assembly against loosening from shock and vibration so fastener clamping forces are maintained. Threadlockers also seal the threads against leakage and prevent rust and corrosion. Available in a variety of strengths and temperature ranges, Threadlockers remain the most reliable way to lock and seal threaded fasteners of all shapes and sizes, either before or after assembly.