Permatex ThreadlockerOur engines and the roads and trails we take cause vibrations. Applying a strip of threadlock on nuts and bolts helps to keep your fasteners fastened instead of vibrating loose.PermatexThreadlockers 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 by filling the space between threaded metal parts, curing to form a tough, adhesive bond and seal. They also seal the threads against leakage, preventing rust and corrosion. Threadlockers remain the most reliable way to lock and seal threaded fasteners of all shapes and sizes, before or after assembly.Blue/Medium Strength Thread Lock Features: Ideal for fasteners ranging 1/4" to 3/4" (6mm to 20mm) Prevents fasteners from coming loose due to vibration Removable with hand tools for easy disassembly 0.20oz (6mL) Red/High Strength Thread Lock Features: Ideal for fasteners ranging 3/8" to 1" (10mm to 25mm) Prevents fasteners from coming loose due to vibration May require heat for removal 0.20oz (6mL)