Quick Connect Cable (for NR83 / NRC83 / NRC98 / NRC1111 / NCC1991 only) The QC-2 Quick-Connect cable can double your hot water output with little effort. Use the QC-2 to efficiently connect 2 units together, and enjoy the fact that the Quick-Connect system is as versatile and flexible as your lifestyle. Quick-Connect: As hot water needs increase and decrease in a home, the Quick-Connect feature of the Noritz tankless hot water heaters enables more than one unit to be connected in a quick, simple and safe manner. Features: Links two tankless water heater units together Allows for communication between the units Instantly doubles the hot water output Use only one remote Introducing the latest advancements in tankless water heater technology for your home, Noritz tankless hot water heaters are both eco-friendly and energy efficient, providing savings up to 40% in utility costs. Their gas water heaters warm water on demand, which means you'll always have hot water and it will never run out.