Item Description: Gastec Tube 27 - Polytec IV (Qualitative) Polytec tubes perform qualitative testing to determine the presence of multiple unknown substances, simultaneously. Box contains complete instructions for use. Polytec IV tests for the presence of ammonia (amines), hydrogen chloride, hydrogen sulfide, chlorine, sulfur dioxide, nitrogen dioxide, acetylene, carbon monoxide, ethylene, phosphine, hydrogen, methyl mercaptan, propylene and carbon dioxide.