NDS Adapter, Connects Pop-Up Drainage Emitter with Elbow to 3 in. & 4 in. Drain Pipes H1241 - The Home Depot
3″ Corrugated Adapter for 5″ Polylok | Drainage Kits
Amazon.com: French Drain Man 4" Corrugated Pipe Adapter (4” Corrugated to 4" PVC) PVC Fittings, PVC Couplings, Corrugated to PVC, Connect Corrugated Pipe to Pop Up Emitter : Industrial & Scientific
Amazon.com: Polylok 4" Corrugated Pipe Adapter (4" corrugated to 4" SDR 35 or 4" SCH 40) : Industrial & Scientific
3" Corrugated Drain Tile External Snap Coupler at Menards®
ADS 3-in x 3-in 45-Degree Corrugated Wye Fittings in the Corrugated Drainage Pipe Fittings department at Lowes.com