The Stormbag is a heavy-duty 18-ounce burlap bag filled with a small amount of crystallized polymer. The polymer can absorb 300 times its weight in water. Dry the bag weighs just 1-Pound In 3-5 minutes submersed it absorbs approximately 4 gallons of water and weighs in excess of 30+ pounds. In effect, it becomes a sand bag. The Stormbag is a green friendly alternative to sandbags for flood control, flood prevention, water containment, or any emergency excess water situation. No sand required-just add water. The Stormbag is a superior tool that is much more efficient and effective than the cumbersome sandbag or similar inexpensive knock offs that violate the Stormtec patented products. Anyone dealing with water, needs a Stormbag. It definitely doesn't have to be storm related. Unlike sandbags, The Stormbag is highly portable (1 small box of 50 bags is equivalent to 1600-pound of trucked in sand), easy to carry and, actually absorbs water making this one of the world's fastest high tech multi-purpose sponge/barriers!