Multi-film Gas Sampling Bags are made of layered films that consist of polyethylene and aluminum films. It has a stronger ability to resist gas permeation than any other films. This kind of bag is widely used in petroleum chemical industry, environmental monitoring, scientific experiments for gas sample collection and preservation. Features: Non-permeable; Opaque - to protect collected gases against ultraviolet light; Do not chemically interact with gases; Simple to maintain and do not require technical training to operate; Shanghai Sunrise Instrument Co., Ltd. is a reliable supplier providing our customers with products produced in China.We can supply reliable quality, competitive price and efficient service.0.5,1,2,5,10L of gas samping bags are general sizes,we can supply other size according to your requirement,too. We are looking forward to your enquiry and your precious suggestion.