Do you mean the external signal wire in the picture which you sent me right?
We did like that in early time, but some customers said it will not good looking,
so the wifi controller signal wire built-in the light now.
You can check the picture as attached, there a button which write " wifi and manual ",
when you turn to "wifi " , then you can use your smart phone to control the lamps.
when you turn to " manual", then you can control lights via the two rotary knob which
on the back of lights.