We are offering gas sampling bags. gc sampling bag 1.high quality 2.customizing is ok 3.with valve to keep gas in(1 valve or 2 valves) 4.you must like to order gc sampling bag1.high quality2.customizing is ok3.with valve to keep gas in(1 valve or 2 valves)4.you must like to order gc sampling bagreplete manufactures and sells various industrial and environment-friend gas sampling devices, including gas sampling bags made of aluminium foil composite membrane, gas sampling bags for fluorine-contained gases, health oxygen bags made of aluminum foil composite membrane and special gases preparation. product introduction: gas sampling bags for fluorine-contained gases: this product is highly corrosion resistant, and can be used for corrosive gases, including so2, h2s, no2 and etc, and prolongs the storing time. specification: 150ml - 40 l, single or double opening (with switch valve), customizing is available.