Connect two lengths of different-sized ABS piping with the 3 in. x 2 in. ABS DWV Hub x Hub Reducing Coupling. The fitting features ABS construction and is built for use with DWV systems to help remove wastewater from plumbing fixtures. ABS DWV is joined by solvent cementing or threading and can easily be connected to steel, copper, or cast iron through the use of transition fittings. Color: Black.