Clear 1.2mil FDA film Todays packaging film for bags is polypropylene. It provides excellent oxygen barrier, which gives the greatest possible flavor retention and freshness longevity, as well as providing a superb moisture barrier. Unlike cellophane, polypropylene will not dry out, crack, become cloudy, deteriorate on your shelf, freeze and become brittle, or take on moisture and pucker. It will seal with the same jaw sealer as cellophane, or with an inexpensive impulse sealer. It weighs less because it is not made from trees.... and costs less because of high tech production.