Featuring a 5.1 Mil thickness and opaque material on both sides, the Bag Chrome King Child-Resistant Smell Proof Mylar Bags (quarter oz) offers superior protection for organic flower from air, light, and skunky odors. Its heat sealable top ensures a tamper-proof seal and an expandable bottom gusset allows it to stand upright. The child-resistant zippered closure allows for resealing of the bag when needed and instructions for the child-resistant feature are printed on the inside.