The dual-action formula of Roundup Ready-To-Use Extended Control Weed & Grass Killer Plus Weed Preventer II with Pump ‘N Go 2 kills existing weeds and prevents new ones from growing for up to four months—and it kills them down to the root, guaranteed! (Consumer Guaranteed: If for any reason you are not satisfied after using this product, simply send us original proof of purchase, and we will replace the product or refund the purchase price.) Plus, the Weed & Grass Killer can be used on driveways, sidewalks, patios, along fences, curbs, retaining walls, and edges of lawns, as well as on decorative rock or gravel areas. The Pump ‘N Go Sprayer with an extendable wand provides 10 minutes of continuous spray! Rainproof in 10 minutes with visible results in 3 hours, Roundup works. Fast.