I-Chem® Brand Tall wide-mouth clear Type III glass septa jars are excellent for multi-purpose use. Supplied with open-top polypropylene closures ultrasonically bonded with a .045" thick PTFE/silicone septa. I-Chem Certified® 200 and 300 Series jars are guaranteed to meet the EPA's Performance Based Specifications for Volatile Organic Analysis. I-Chem® 100 Series bottles are made of the same quality materials and to the same specifications as the I-Chem® 200 & 300 Series jars. However, the 100 Series products are neither processed nor certified.