No-hub fittings, also called soil pipe fittings, are drain, waste, and vent (DWV) fittings that use gravity to divert, divide, or return the flow of water and waste through the pipeline in all types of residential or commercial construction. DWV fittings connect by placing the fitting end against pipe or another fitting. These joints are sealed together using a low-pressure clamp-on connector. Cast iron is strong, crushproof, sound deafening, and corrosion resistant for gravity-flow applications above and below ground where temperatures don’t exceed 212°F. Black fittings include a scaly, dark-colored iron oxide coating. No-hub fittings come in a variety of sizes and shapes.