California Barrier Bags are an economical solution for the packaging of medical cannabis in California. Made of polyester resin, these bags possess good moisture and oxygen resistance properties. These bags are heat sealable for tamper proofing and have a zip-locking mechanism so they can be reclosed as well. These bags are sturdy with a wall thickness of 4.5 mils. These California barrier bags all have an opaque, white backing with our California bear/state logo and warning text and are clear on the front to allow viewing of the bag's contents. It should be noted that mylar bags are not classified as child-resistant.