ALVIN Ice Tubes. Unique transparent PVC mailing/storage tubes in four cool colors. Available in three sizes, 25" , 37" and 43"lengths with 2 3/4" 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 shoulder strap that provides convenient portability. Perfect for students, pilots, contractors, draftsmen, architects, engineers, sportsmen, campers, boaters. Designed for mailing anything that can be rolled – charts, maps, blueprints, posters, etc. Protects against creases, bends, tears and folds.