Check the listing for details. Flex-Drain 4 in X 12 ft Polypropylene Perforated Drain Pipe 51910. Condition: New. Listed at 29.99 USD. This 4 in. x 12 ft. pipe has spaced slits that allow water to drain in stages. It's ideal for ground water drainage like French drains or dispersing water from flower beds. Flex-Drain helps you get the job done faster and easier, with professional grade durability and more versatility than traditional corrugated pipe. Flexible and expandable, Flex-Drain easily bends around any obstacle, holds its shape during installation and with a simple snap, its integrated fittings lock securely and stay connected during back-filling. Taping joints is not necessary. More than just pipe, Flex-Drain is a complete drainage solution system that's widely compatible with virtually all traditional 3 in. and 4 in. corrugated pipe and 4 in. PVC.