Our 16" x 18" 4 Mil High Puncture bags are Heat sealable, electrostatic protective, moisture protective multi-layer laminated material for ESD safe and moisture barrier packaging. All 16 x 18 4 mil High Puncture Bags are made from PET, AL, NY, PE, Static Dissipative Coating and can be recycled. Our flat open top 16" x 18" .004 High Puncture Bags has a combination of polyester, nylon, aluminium foil and polyethylene that makes it an extremely tough structure for transportation purposes and long-term dry-packed storage of sensitive devices. These 4 High Puncture 16 inch by 18 inch bags are able to be sealed effectively with a vacuum sealer and should use desiccants for added moisture protection.