This product is a patent-pending, innovative 4 in. x 100 ft. perforated flexible single retaining wall drainpipe with alternating sections of flexible and standard corrugated sections. The product provides the same lightweight, durable and low-cost drainage solution as its competitors in a more compact and versatile package. Flexible expandable sections allow for the product to be packaged in a more compact footprint which allows for an improved storage/transportation process, reduces memory when unfolding, bendable and provides a built-in elbow every 4 ft. if needed in applications. The product features a light-weight polyethylene construction for durability and exceeds all ASTM standards. Great for landscaping purposes such as leach fields, culverts and french drains