Fernco 4 x 6 in. Fernco 1002-46 Flexible PVC Pipe Coupling for Clay to Cast Iron, Plastic or Steel Plumbing Connections, Black 1002-46 - The Home Depot
Flexible Coupling, For Pipe Size 6" x 6": Pipe Fittings: Amazon.com: Tools & Home Improvement
Fernco 6" Cast Iron/Plastic Shielded Flexible Coupling at Menards®