Using an automatic timer eliminates the need for you to manually turn lights on or off. The Outdoor Digital Dusk-to-Dawn Plug-In Timer with Photocell takes care of this process, offering a more convenient and secure home environment while promoting energy conservation. It has a weather-resistant casing so it can be mounted in an indoor or outdoor setting and can be used with almost any two-pronged plug-in light setup. The timer will be activated when the photocell senses that the ambient light level is at darkness. You can also set the amount of time you want the power to remain once it is active, from one hour to nine hours. Use it for a few indoor and outdoor lights to keep you from coming home to a dark house or to give your home that lived in appearance to help deter criminals. If you are someone who simply forgets to turn off the lights at night, let the timer do the work. By limiting the amount of time your lights are on after dark you can significantly reduce the amount of energy being used as well as the asscociated costs.# Outdoor Digital Dusk-to-Dawn Plug-In Timer with Photocell # Owner's manual.n dawn to dusk mode, the digital timer will turn on when it senses darkness, whether it is indoors or outdoors. The length the timer remains on is dependant upon the amount of time you program, from one to nine hours. Keep in mind however, that if the digital timer receives enough light to come back on, it will reset and the countdown timer will start over again. The timer can also be turned on and off manually.