Plastic telescoping plastic tubes are expandable and designed for storing or shipping anything that can be rolled: charts, maps, blueprints, posters, drawings, artwork, etc. Protects against creases, bends, tears, folds. Great travel carrying tubes. Available in several diameters and lengths. Telescoping poster tube includes an adjustable shoulder strap for convenience and portability. Choose from Alvin ZOOM Tubes, TS2, ALTUBE, Chartpak Expand-a-Tubes, and the popular Black Knight BTR4. Alvin and Chartpak telescopic extendable plastic blueprint tubes.