Gas sampling bags are constructed of 2-mil thick tedlar with solid seam to keep gases contained. Unique, polypropylene combination Valve features 3/16 inch OD on/off stem suitable for tubing connections and integral PTFE silicone septum for syringe sampling. Low permeability. Select from a variety of sizes to suit your needs. Case of 10. Single fitting features both on/off Valve and septum port for added convenience solid seam construction for added strength corner opening with grommet allows tagging or hanging during transport and storage includes certificate documenting lot compliance.