Product name:coffe Bag The coffee bag is made by multi-layer structure such as OPP/ALU/NY/LLDPE,PET/ALU/NY/LLDPE, PET/ALU/LLDPE, etc. These materials have low OTR AND WTR properties, it is a great packing for ground coffee, coffee beans, coffee power and other foods which are sensitive to oxygen. The bag can be welded with one way transmission valve which will pull the carbor oxygen (CO2) out, and prevent the outside air to enter in.