Our 10" x 20" 4 Mil Foil bags are heat sealable, moisture protective multi-layer laminated material for effective moisture barrier packaging. All 10 x 20 4 mil Foil Bags are made from PET, AL, PE, Static Dissipative Coating and can be recycled. Our flat open top 10" x 20" .004 Foil Bags has specially selected polymers that reduce ionics, NVR and outgassing. These 4 Foil 10 inch by 20 inch bags are able to be sealed effectively with a vacuum sealer and should use desiccants for added moisture protection.