Metallic Foil Heat-Seal Bags, 2.5 mil SilverPAK w/ Tear Notch, 2.5 mil SealPAK 600 series. Pre-made pouches are sealed on 3-sides. Choose your preferred product from the drop-down menu. Metalized Polyester Three-Side-Seal Barrier Pouch. Ampac's SilverPAK is a 2ply laminated structure consisting of metalized polyester and polyethylene (METPET/PE). These metalized pouches are ideal for powders and other granular materials. SilverPAK Known Uses: Packaging fine powders and other granules Repackaging medicine for animals Packaging dental extrusion cartridges Seal using Ampac's multi purpose heat sealer.