Inficon Compass HVAC Refrigerant Leak Detector 717-202-G1 features innovative heated diode sensor technology - providing exceptional sensitivity to all refrigerants, yet resisting other contaminants such as dust, dirt, and oil. The Inficon Compass operates on rechargeable batteries or AC power, has adjustable high/low sensitivities, and a ergonomic rubberized grip handle for easy one-handed operation.