The NexusST includes a Master Unit (Site Manager) and a Control Box (Heater+)
The NexusST Site Manager Box has 3 configurable sensor inputs on the left side of the box for: Temp/Humidity, Embeddable Temp, and a Fuel Level Sensor.
The C1 port on the bottom of the Box is a Control Output where the Heater+ box plugs into. The yellow cable on the Heater+ Box plugs into the Construction heater to toggle the heater ON/OFF based on user specified interactions.