The POPULAR Chart Holder is an economical storage for all the important documents, blue prints, posters, paper rolls, scrolls, maps, sketching papers, architect papers, etc The lock and unlock system and strap makes the sheet holder extendable and portable. The plastic body of the container protects the artwork from fading due to exposure from light and nominal water. For this price, it’s a must have for all enthusiasts, engineering students, art students, architects, designers and artists!