MARS - Leak Lock joint sealer is a soft-setting pipe joint compound for sealing threaded joints, flanged joints, gasket surfaces and mating surfaces. This resin-based brushable paste remains permanently flexible, adheres to internal surfaces and fills voids. It is ideal for use on metal and plastic materials subject to extreme vibrations, temperatures from -100°F to 400°F, full vacuums to 10,000 PSI. Leak Lock seals all refrigerants (R12, R22, R502, R134A, etc.), petroleum products, natural and manufactured gases, steam, water, air, etc.