These lightweight durable tubes, made of virgin high density polyethylene, are water-resistant and ultraviolet lightproof. Ideal for storing, mailing, or transporting. 26 5∕8" long tubes can expand in length, 12" at a time, by adding optional middle sections. Ideal for storing items like school banners or flagpoles. Gray tubes have a 2½" inside diameter, black tubes have a 3½" inside diameter. Middle Section.