How often do you forget to switch off outside security lights? Sometimes because there was power outage when leaving home only to return and be told that there has been power (light) since you left home with your outside lights (bulbs) draining your power-recharge.
Now you can solve that with this device.
It would automatically switch off your outside light once day breaks.
When used with your inside switch, you control if and when it would switch on the light.
But on standalone, it would switch off and on the outside lights when day breaks and when darkness sets-down.