Biodegradable-Compostable with Kraft Paper + Aluminum (has aluminum layer/PVOH/PBAT)—seriously—per TUV-BPI certification, the proportion of aluminum (not compostable) is tiny and not deemed harmful). This structure excellent for under 12 month shelf life… laundry powder, chocolate, freezer/frozen products, some liquids without corrosive elements). Maximum thickness 4.7 mils or microns and maximum weight 6.5 pounds.