(Vellum) These see-through products not only make intriguing mailers, they have archival qualities. Use them to really showcase your invitation, or mailing, or store old documents, and photos. Made from 100% pure cellulose fiber without resins or other transparentizing agents. 30 lb. stock is translucenct, recyclable, acid free, and elemental chlorine free. In colors and frosty clear.