Other plastic bags are usually made of one layer of polyethylene (a type of plastic). FoodSaver® Bags are 5-layer including an outer layer of nylon. The nylon layer not only makes the bags stronger, it also creates a complete air, moisture and odor barrier. Unlike other bags, FoodSaver® Bags can be simmered in water or microwaved (so you can reheat leftovers or pre-cooked dinners).