GAS LEAK DETECTOR, LOW TEMP Leaks appears as large strong bubbles which cling to the surface and are fluorescent under a black light Non-freezing Non-toxic Non-hazardous Fluorescent, Yellow-Green Rated to -30°F (-34°C) to 200 F Bubble-type gas leak detector Used on: Hot and cold piping, natural gas,most gases, air and all refrigerants. 8 oz. plastic bottle w/dauber.