Adjustment of sensitivity: Carefully the unit features 5 levels sensitivity adjustment, Slower and closer movement of the probe greatly improves the likelihood of finding a leak. When the gas leakage are discovered, Will hear "di di" sound . More refrigerant leak, more rapid, meanwhile the indicator light flash quickly. Upgraded: At each area checked, the probe should be moved around the location, at a rate no more than 25 to 50 mm/econd(1-2in/second). And no more than 5mm(1/4in) from the surface, completely around the position. When the leaked gas is detected, the audible tone will change to a "siren" type sound. More refrigerant, more siren. At the same time, Digital display screen display corresponding sensitivity quickly Easy set up: The leak detector features an automatic circuit and a reset function that set itself to ignore the ambient level of Halogen gas. Upon initial switch-on, keep in 6s and enter into the best state of detection. Widely use: It can detect all kinds of halogen refrigerants including , HFOs, CFCs, HCFCs, HFCs and mixed refrigerants such as HVAC, R22, R410A, R134A, R1234yf ...It can be used for almost all air-conditioning refrigeration, including car and household air-conditioning and equipment refrigeration. The working temperatureis 0 - 52(30 to 125), Maximum sensitivity is 0.14oz/yr(halogen refrigerants). Electricity source need 6v DC, 4 x AAA batteries(not include). Colour:Red & Black Material:ABS Size:22.9 cm x 6.5 cm x 6.5 cm (9.01 x 2.56 x 2.56 inches),Fixed probe length:20cm (7.87 inches) Package Contents: 1 * Air Conditioning Refrigerant Leak Detector Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.