Flex-Drain ADP53102 Downspout Adaptor, Landscaping Drain Pipe Adapter 3 by 4 by 4-Inch Compatible with most traditional 3-inch and 4-inch corrugated pipe and 4-Inch PVC. Installs faster than traditional corrugated pipes and requires 80% less space for transport and storage. FLEX-Drain's unique flexibility allows it to fit in tight spaces and curvy places. 30-Percent higher load-bearing rating than standard corrugated pipes. Integrated soil-tight fittings lock securely and are perfect for French drains, downspout drain pipe and more!