The Seawhite Drawing Tube has a 4" diameter made of a very sturdy and rugged black plastic. The telescoping tube can be adjusted from a closed 30" length to a fully open 49" length. Twist-lock notches for secure storage and transport at desired lengths. Made of rugged black plastic, tube is water-resistant as well as nearly light proof. It's ideal for many of uses with it's adjustable carrying strap that allows the tube to extend while making it easy to transport. The adjustable handle makes it convenient to "balance" the tube when it's loaded. This is a high end, heavy duty drawing tube that can accommodate nearly all sizes of documents.