Blue Monster® Microbubble leak detector is a sensitive solution formulated to detect even the smallest of leaks in air and gas lines, tanks, cylinders, valves, fittings, pipelines, and other suspect areas. Blue Monster's dependable formula provides long lasting leak detection up to 10 minutes after application. Ideal for identifying leaks in refrigeration and air conditioning systems, this easy-to-use leak detector is equally effective on natural gas, propane, butane, air, nitrogen, chlorine, CO2, and most other gases. Detects even the smallest of gas leaks Non-freezing formula, usable from -10F (-23C) to 215F (101C) Will not cause corrosion or deterioration of metal or plastic piping systems Ideal for testing pressures less than 1 psi