Fernco® P1004-66 Flexible Coupling for Concrete To Concrete Pipe, 6" x 6"The dimensional flexibility of Fernco couplings ensures leak proof seals on virtually any pipe material. All couplings are clearly marked with part number, size, and pipe material that the coupling will connect to. 6" x 6" flexible coupling Connects concrete to concrete pipe Tested designs backed by over five decades of proven performance Positive seal against infiltration and exfiltration Leak proof, root proof and are resistant to chemicals,