Test all refrigerants containing halogens. Test for all halogen gases including chlorine/fluorine/bromine, CFCs R12, R11 R500 R503; HCFCs R22, R123, R124, R502; HFC R134a R404a R125, also tested AZ - 50, HP62, MP39 High precision gas tester, tell you exactly where the leak is. 7 degree adjustable sensitivity, munual; also with auto-adjustment to optimal detection state The detector is self-triggering and auto-tracking reset function which can ignore the concentration level of halogen gases in the environment. USES high-quality sensors, high-sensitivity work, long life expectancy Built-in voltage, high precision, and the use of ultra-low-power IC, making work more stable Batteries take turns, and on, Stared check lines, halogen gas detectors will tell you where the leak is, it took less than a minute to find it. Can be used in automotive air conditioning system