Art Envelopes 33X36: Ideal for artists, architects, engineers, pilots or anyone who needs to store and protect important artwork, photos, graphics, maps, or documents. The envelopes are made from heavy-duty .010" crystal-clear vinyl, heat sealed on three sides. Fourth side of the envelope is open with flap to hold the art, graphics, maps, or photos in place and protect against dust, dirt and moisture. First dimension (width) of envelope is open side. Includes an acid-free black paper insert. The envelopes are designed to fit standard size sheets and portfolios for placing drawings, graphics, artwork.