Everything in the Classic Roll-Top series is built just like a traditional roll-top dry bag. The full RF-welded construction ensures a water-tight body. And you just need to roll the top down with 3 or 4 rolls and secure with buckles to keep out the water. When properly sealed the Classic Roll-Tops will even float on top of the water. The Classic Roll-Top Backpacks each feature a seamless PVC interior and an attractive nylon fabric exterior. Each waterproof backpack features a padded back, padded adjustable shoulder straps with sternum strap, an adjustable waist belt, a top carry handle, and an exterior bungee harness system.