All you need to do is add water. Sandbags that don't need sand. This is no science fiction, this is the StormBag. The StormBag weighs less than 1 lb and rapidly expands to ~30 lbs in just three to five minutes. StormBags eliminate the need to stockpile sand as well as the heavy equipment and personnel required to fill and deploy traditional sandbags. Expands in freshwater only.