Flash™ UV dye is an advanced class of highly concentrated ultra violet dye that uses DRY R™ instead of POE oil as its carrier. This, combined with our patented misting action, enables the dye to travel at the speed of the refrigerant while keeping the dye stable. One can treats up to 64 oz (1.8L) of oil. Flash UV dye uses the systems refrigerant as the propellant, creating a clean, no-mess injection every time. The 20122 reusable hose is required - sold separately.