General Tools RLD400 Digital Refrigerant Leak Detector, with Pump New proprietary semiconductor sensor with more than three hundred hours of operation that detects refrigerant leaks Features a triple-redundant leak indication (loud fast beep, flashing LCD and digital leak size reading) and has three different sensitivity levels Comes with a mechanical pump that draws in samples that increase sensitivity; auto-calibration, unit will reset to ambient levels The comfortable neoprene grip fits great to the hand and the beeper is mutable; the sensor comes with a padded hard case and is garage durable Made in the U.S.A. with a 2-year limited warranty; 4 AA batteries are included