Phosphine detection tube 7 PH3 Phosphine Measurement Range 2.5 to 5 ppm 5 to 50 ppm 50 to 100 ppm. The detection tube can be used not only for indoor air detection, air quality monitoring in public places, harmful gas detection boxes for air and specific gases in work sites Rapid qualitative and semi quantitative detection of toxic and harmful gases in emergencies. The rapid gas detection box for sudden accidents is mainly used for sudden gas leakage accidents and emergency rescue