This plug has a light sensitive "eye", that automatically turns the night light on when it gets dark, and turns it off when the room gets lights. This one is a great convenience for those who don't want to be bothereed with turning it on and off.
Please note that there is no over-ride, the night light will be on when its dark and off when light. If you want to be able to control whether it is on or off, I suggest you stay with the standard on-off switch plug.
Please note also that this plug works best with an incandescent bulb; it does not work well with some LED's.