Final answer:
The connector needed to attach plastic DWV to cast iron DWV is a hubless connector.
Step-by-step explanation:
The connector needed to attach plastic DWV (Drain Waste Vent) to cast iron DWV is a. Hubless. Hubless connectors are used to join different types of pipes together, including plastic and cast iron. These connectors have a gasket that forms a tight seal between the pipes without the need for glue or solvent.
For example, a hubless connector can be used to connect a plastic DWV pipe to a cast iron DWV pipe in a plumbing system.