Cleveland Tubing 53102 3x4BLK DNSPT Adapter, 3" x 4" x 4", Flexible Downspout Adapter, Use To Connect Your Downspout To Flex-Drain, 4" Standard Corrugated Pipe, 4" PVC, & Most Other 4" Pipe, Allows An Easier Connection With More Versatility Than Standard Rigid Adaptors.