Gas leakage tester diagnostic tool for automobile air conditioning systems, air conditioners, refrigeration systems & refrigerant recovery devices. Reacts to all halogen gases (including chlorine and fluorine), but it is not limited to the gases listed below: CFCs e.g. R12, R11, R500, R503 etc. HCFCs e.g. R22, R123, R124, R502 etc. HCFCs e.g. R134a, R404a, R125 etc. This unit can also detect other mixtures, such as AZ-50, HP62, MP39, ethylene oxide gas leaks on medical equipment (detection of halogen thrusters), SF-6 in high-voltage circuit breakers & more. Detection of fluorine, chlorine & bromine (halogen gas) as well. Detection of halon gas in fire extinguishing systems. Operation: Indicator light warns of leakage & battery voltage indication. Adjustable sensitivity, or the instrument can automatically adjust to the best detection state. After unit is powered on, the unit automatically adjusts within 6 seconds to ignore any existing level of refrigerant. The concentration level of the refrigerant is then detected. Beeps regularly when on. If a leak is detected the unit beeps faster. Maximum sensitivity: 6gr/yr(halogen refrigerants).