These durable circular woven polypropylene bags are 1600-hour UV stabilized. That means these bags will Bags will generally retain 70% of their strength after 1600 hours of exposure to sunlight. They provide a great economical solution for flood and erosion control due to their sturdy design and low price. They also work great for highway barriers and other traffic and construction applications. They have attached heavy poly-twine ties which provide a secure closure for the bag. Sold in bales of 1000. Weighing 40 pounds when filled.