Prestige™ Alvin Art Envelope 15 X 19 - Pkg of 6 Congratulations. You just spent three hours drawing your surroundings on charcoal. Frankly, it looks pretty good. With a pleased smirk, you give it one last once over, but grimace as the sky begins to opens up and tosses a raindrop right on your head. In the old days, you would put your work in your sketchbook, hunch over the book, run to the safety of your car and hope for the best. Fortunately, today, you purchased Prestige™ Art Envelopes made of perfectly protective Clear Vinyl!