Mastercool 55850 Intellasense Refrigerant Leak Detector Kit with Optimum Life Sensor is designed to detect all refrigerants including CFC’s, HCFC’s, and HFC’s. The Mastercool 55800 features a 16” flexible probe, sensitivity down to 0.05 oz/yr, clear and intuitive colored LCD display, 2,000-hour sensor life, and high/medium/low sensitivities.