Alvin Blueprint Bags make packaging and shipping blueprints hassle-free. White Exterior /Gray Interior opaque bags are made of heavyweight .0035mil. co-extruded plastic material. These weather and tear resistant envelopes are extremely durable and easy to use. Bags are designed with a permanent self-sealing 3” lip. Bags accept self-adhesive labels and permanent markers with ease. 10” x 38” + 3” lip. 100/box.