Constructed of 2 mil Tedlar PVF fluoropolymer film. Available with either a nickel-plated brass on/off valve which accepts 1/4"" I.D. flexible tubing or PTFE/silicone septum in polypropylene housing for use with a hypodermic needle. For analysis of non-corrosive gases such as carbon monoxide, sulfur dioxide, hydrogen sulfide, radon and mercaptans. Cited in Title 40 CFR, PT. 60, App A Meth. 18. Packaged individually.