Woven black polypropylene fabrics have excellent permeability to let air, water and nutrients through while blocking the light required for weed growth. Its the ideal choice for safe weed control and water conservation. UV-treated. Striped every 12 to aid in planting spacing. Sunbelt Weed Fabric is 3.2 oz/yard, and this high-grade fabric blocks 99.7% of light, and resists tearing, puncturing and weed penetration. It is approved for most government weed control applications. It typically lasts 8-12 years, according to the manufacturer who guarantees the product for 5 years against UV breakdown. The 6' x 6' size is perfect solution for controlling weeds around the bases of trees.