As pictured, the  Interface  is simply plugged into one side of the floodlight fixture;  the user connects two low voltage wires from the terminal strip of this relay to the sensor terminals of the Flex ECT. It is important to note that the Interface  itself draws too little current for the proper operation of some floodlight fixtures. So it might be necessary to use at least one 50 watt bulb, in addition to the Interface.   If light at the floodlight location is no problem, just put the bulb into the other side of the fixture;however, if light is undesired at this location use a portable light (as pictured above) that can be hidden from view or directed elsewhere.