Microprocessor controlled circuit with advanced digital signal processing. Detects R12 and R134a refrigerants. Certified to SAE J1627. Variable frequency audible alarm. CE approval, UL classified. Constant power indication. Cordless and portable; operates on two C-cell batteries. 14" flexible stainless steel probe with liner. Six-segment visual leak size indicator. True mechanical pump provides positive airflow through sensing tip. High and low sensitivity levels. Tactile keypad controls.