Getting your blueprints to a distant destination can be nerve wracking. Will it be damaged by rain or from falling in a puddle? If the package is opened, how will the blueprints fare? When you pack your blueprints in a polyethylene shipping bag, you know that it is protected from the elements. The .004 mil of opaque polyethylene keeps your blueprints safe in a bag with a 3" lip. Just slide the paper in and seal it away with the adhesive strip on the lip. Don't take the chance that something so easy to protect against will mean the end of your hard work. With 100 bags in this pack, you'll have plenty on hand when its time to ship.