Durable Mylar sleeves are made from acid-free polyester. Mylar is usually 2 mil to 4 mil thick as well. So, this makes it thicker than most other comparable comic book protection products. Mylar is probably the best standard for protecting your comic book products. If you use Mylar sleeves and backing boards properly, then your comics will have protection from the elements for a lifetime.
A lot of government offices and research facilities, like the Library of Congress, use Mylar to protect vital documents and records. Such lifetime guarantees are known as an “archival standard.”
