J-B Weld Threadlockers provide a reliable and superior lock and seal for threaded fasteners. Ideal on mechanical parts, body assemblies, and hundreds of other applications to prevent loosening of fasteners from shock and vibration. The perma-lock low viscosity green thread locker penetrates between part surfaces for a secure seal with no disassembly necessary. It can be applied to pre-assembled parts and is ideal for 1/2 inch to 2 inch fasteners.