Kills and prevents weeds for up to 12 months by creating an invisible barrier in the soil Kills weeds to the root Use Roundup weed killer on driveways, patios, sidewalks and gravel areas Rainproof in 30 minutes Visible results in 12 hours Consumer Guarantee: If for any reason you are not satisfied after using this product, simply send us original proof of purchase and we will refund the purchase price Cover up to 1,600 sq. ft. with one bottle of weed killer Includes 32 oz. of weed killer concentrate Note: People and pets many enter treated area after product has dried; the main active ingredient in Roundup Weed and Grass Killer products is glyphosate; it works by targeting an enzyme that is essential to plant growth