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 hold its shape during installation and with a simple snap its integrated soil-tight fittings lock securely and stay connected during backfilling. This solid expandable pipe will only let water seep in or out at pipe ends. 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. Technologically superior it s made with no-break copolymers and exceeds all applicable ASTM crush standards