Made of polyethylene, aluminum foil and mylar, it has tear resistance and durability. 100% food grade material, FDA and USDA compliant, non-toxic and tasteless, can be directly used in food packaging. Quality smell proof bags are recyclable that you can repeat open the zipper, the sealing strip is very tight and don't broken. So, you will never worry about whether the mylar bags are open or close. Smell proof bags has two cuts on the above, you can tear aluminum zipper bags quickly and easily.