Mission Rubber 300043 CP 43 Band-Seal Specialty Coupling, 4-Inch Cast Iron to 3-Inch Plastic/Steel/Extra-Heavy-Cast-Iron Corrosion-resistant 300 Series stainless steel components Internal rubber sleeve reduces noise and vibration Easy to assemble, disassemble, and reuse Neoprene rubber sleeve conforms to ASTM C 564 Band-Seal Specialty Couplings conform to ASTM C 1460