HDE Refrigerant Leak Detector HFC CFC Halogen Freon Air Conditioning Tester Adjustable Sensitivity HVAC Inspection Tool Save money and avoid expensive repair bills | Leak tester detects Halogen based HFC, CFC and HCFC refrigerants including but not limited to R11, R12, R500, R503, R124 Adjustable sensitivity can changed in real time to adapt to different operating environments | Tester has seven sensitivity levels that can be easily adjusted via front dial Flexible neck detection nozzle makes getting in to tight spaces easy | Perfect for detecting leaks in hard to reach places such as cars, kitchen appliances and home AC units Battery voltage display LED let's you know if your leak detector is working at optimal levels | Green LED light indicates normal operation, Orange light indicates less than optimal performance Package Contents: 1x Leak Detector, 1x Carry Case, 1x Instructions | Requires 4x AAA batteries for use (not included)