Generally speaking, the Stand Up 12oz Foil Coffee Bags Black With Degassing Valve ( can be also customized ) is produced using the best materials: Printing (Surface) Layer: BOPP, PET, NY, KRAFT PAPER, RICE PAPER; Barrier (Laminated) Layer: NY, PET, PETAL, AL; Heat Seal (Inner Food Contact) Layer: HDPE, LDPE, CPP, CPPAL, RCPP.The matte black stand up pouch in the picture is composed of a material that is water-repellent.The extremely strong waterproof performance ensures that your product will be protected from moisture, mildew.Moreover, it is lined with a heat-sealable poly material that prevents air leakage.And with that, it boasts two small tear designs on both sides and a recloseable zipper, which are convenient, fast and easy to open.The thickened bottom design and the application of oil pressure edge sealing technology make it stand better to a limited extent.