Cleveland Tubing Inc 50910 4'' Expandable Perforated Drainage Pipe Size: 4" x 12', Black Expandable Perforated Flex-Drain, Can Be Used In Most Drainage Applications Soil Tight Fittings Are Built Into The Pipe &amp; The Pipe Holds Its Shape After It Is Bent Therefore No Other Connectors Are Needed Simply Dig Your Trench, Lay Your Flex Drain Pipe &amp; Cover It Up