These clear PVC extendable tubes safely and securely store evidence. A unique twist-lock action holds contents securely in place. The tubes can be twisted to the exact height needed. The smaller unit can extend from 17-33cm 7-13 inches and the larger tube extends from 33 to 61cm 13-24 inches. Each tube has a hexagon end to prevent rolling. They are durable, reusable and oil and moisture resistant.