These Charging Stations were designed so you can set all of your rechargeable battery powered devices to charge without the fear of wasting energy. The LPG prevent idle power loss and overcharging due to fully charged devices still being plugged in. The way it works is you plug in all of your chargers so the Charging Station knows how much power they are consuming WITHOUT any devices being charged. Now, plug in your devices to be charged, press the button on the side of the unit and walk away! When the last device is fully charged and stops drawing power, the Charging Station will notice the same level of power draw when there was nothing charging and automatically shut off the Charging Station to prevent idle power loss. All of this and you are still getting a top of the line surge protector.