Flex-Drain ADP53302 I.D. to 4-Inch I.D. Pipe Connector, Landscaping Drain Pipe Adapter I.D to I.D. pipe connector features an inner dimension that connects to 3 In. pipe and an outer dimension that connects to 4 In. corrugated pipe and PVC pipe Primary use of the I.D. to I.D. Universal Connector is to connect the FLEX-Drain system to other corrugated and PVC pipe Will not connect to other FLEX-Drain accessories except the female end of the FLEX-Drain pipe Exceeds all applicable ASTM Standards Compatible with most traditional 3 in. and 4 in. corrugated pipe and 4 in PVC ;The FLEX-Drain system has a 30-Percent higher load-bearing rating than standard corrugated pipe