The Techno Tools Refrigerant Gas Leak Detector, No. D440A, features long life heated sensor technology designed to detect HFC refrigerants such as R-134a in addition to all HCFC and CFC refrigerants including hydrocarbon blends. The digital display is independent from the audio alarm and sensitivity level, allowing the precise pinpointing of the leak source. The D440A features three adjustable sensitivity levels, true mechanical pump, low battery indicator, and automatic calibration and reset to ambient levels. It is also SAE J2791 and CE certified, uses four AA alkaline batteries, and is made in the U.S.A.