Roundup Dual Action Weed & Grass Killer with Pump 'N Go, 1.33 gal. features a powerful dual action formula that effectively kills existing weeds and grasses down to the root. It also prevents new weeds from growing for up to four months by creating an invisible barrier in the soil. This product is for use on driveways, sidewalks, patios, around trees, landscaping areas, along fences, and gravel areas. For results, apply during warm, sunny weather above 60 degrees Fahrenheit. It becomes rainproof in just 30 minutes, with visible results appearing in as little as six hours.