Seals micro leaks in condensers, evaporators, O-rings and hoses. Can add years to older, out-of-warranty ACR systems that leak small amounts of refrigerant. Works with all popular refrigerants and oils _x000D_Non-polymer, oil-soluble formula safe for system components and recovery equipmnt. Meets ASHRAE 97 standard for chemical stability_x000D_. Can be injected with the system off or running. Available in three convenient delivery methods._x000D_