Alvin Ice Tubes...Unique transparent PVC mailing/storage tubes in four cool colors. Ice tubes are 37 inches long with 2-3/4 inch inside diameter. One end of the tube is permanently sealed while the other end allows easy access. The tubes are moisture proof and come with an adjustable nylon web shoulder strap that can clip on or off for convenience and portability. Perfect for students pilots contractors draftsmen architects engineers sportsmen campers boaters. Designed for mailing anything that can be rolled â charts maps blueprints posters etc. Protects against creases bends tears and folds.