Premium performance in an ergonomic, rugged design. Infrared (IR) sensor exceeds current SAE standards for sensitivity. Find leaks of 0.1-oz./yr. Doesn't trigger on oil or moisture like other sensors. Advanced sensor lasts many years without replacement. Water-blocking filter for added protection. Visual/audible alarms trigger on CFCs, HFCs, HCFCs or blends. Self-calibrates for testing in contaminated environments. Features: non-conductive sensor arm; rechargeable 8-hour lithium-ion battery; peak and mute buttons; % battery charge check; magnetic hanger.