Case / 50 1 1/2" x 12" Clear Plastic Mailing Tubes with RED End Caps These tubes are made out of polycarbonate, a durable lightweight material with superior clarity. Reusable, weatherproof tubes are great for shipping or storing your products or documents. The tubes are approved by the U.S. Postal Service for mailing. The RED friction fit caps do not require any adhesive to stay on through the mail. Tube Length and Diameter are inside, usable space.