A Multiwall Valve Bag is a common industrial packaging style designed to package a wide variety of dry flow able products. Valve bags are packed on equipment that deposits material into the bag via horizontal filling spout. It is constructed of several layers of paper. Stick with just paper, or select a construction which includes a poly-coated interior to provide an added moisture barrier. It is often used as shipping and storage containers for bulk materials. Multiwall Valve Bag is made up of at least several layers of paper products to include inner ply and a printed external layer.