The Haltech CAN wideband O2 sensor kit includes everything you need for plug and play operation when used with a Haltech Elite ECU. Simply connect the CAN-bus cable between the WBO2 controller and the ECU, and connect the sensor(s), and you're installation is complete. These controllers can also be used with non-Haltech or non-CAN-bus equipped ECUs when used with the included power harness that can be connected to switched 12V and also allows for an analog 0-5V output.
Basic controller kit allows connection to the ECU for logging and closed-loop O2 control. A gauge should be added to the kit if you need an external display. If you're pairing the controller with a display dash, a display gauge would not be needed.
Single sensor kits include controller, harness, and one (1) NTK sensor. Dual kits include controller, harness, and two (2) NTK sensors.