Mastercool, 55800, IntellaSense Refrigerant Electronic Leak Detector With LCD55800 Includes only:Blow molded case2 "D" batteriesLeak test vialReplacement filtersDetects:Combustible GasesHydrogenRefrigerants: All CFC's, HCFC's & HFC'sThe leak detector employs a new metal oxide gas sensor for the detection of chlorofluorocarbon gasses and blends. This tin oxide sensor is characterized by high sensitivity and a fast response, upon detecting the presence of extremely small levels of chlorofluorocarbon gases. Integrated into the design is a powerful microprocessor that automatically selects the best operating conditions for the sensor, to ensure optimum performance. The optimum sensor performance is maintained and monitored throughout the life of the sensor.LCD Features with all optional accessories:WAIT: This indication flashes whenever the unit is in the wait mode. This could occur whenever the unit is turned on or interference is detectedREADY: This indication appears when the unit is ready for useINT: This indication appears whenever the microprocessor detects conditions that are not suitable for reliable leak detection. Excessive wind blowing, blocked probe (no air flow), burned out fan, or a missing or defective sensor that needs to be replacedBATTERY SYMBOL: When the battery symbol becomes illuminated this is an indication that the battery is low and needs to be replacedH - M - L: High, Medium and Low sensitivity ranges will be displayed accordingly based on the selection made on the keypadSIGNAL LEVEL BARS: There are 10 vertical signal level bars on the display corresponding to the level of signal detected by the unitERROR SIGNALS: E1 through E9 indicates diagnostic signalsKeypad Functions:ON/OFF: Press the ON/OFF button on the center of the keypad to turn the unit on or offVOLUME/MUTE: Press the VOLUME/MUTE button to control the volume of the unitH M L SENSITIVITY: Press the H M L SENSITIVITY button to select the desired sensitivity levelHOLD: Press the HOLD button to freeze the signal bars. Press the HOLD button again to disengagePEAK: Press the PEAK button when multiple leaks are suspected as being present.