Fernco® P1006-43 Reducing Flexible Coupling, 4" x 3"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. 4" x 3" reducing flexible coupling with 2 stainless steel clamps Connects concrete to cast iron or plastic Tested designs backed by over five decades of proven performance Positive seal against infiltration and exfiltration Leak proof, root