Gizmo Supply Pro Air Conditioning Refrigerant Halogen Freon Leak Detector R134a R410a R22a Excellent high sensitivity sensor, 6g/yr (0.2oz/yr) Detects All KINDS OF halogenated refrigerants Flexible stainless steel probe reach to almost any tight space Dual-color LED indicator light Adjusts automatically to the best state of detecting, no manual-adjustment needed