Light Seller&reg; Infrared Detector Automatic On/Off LED Night Light for Key Hole/Door Lock (FYD-L0403) This is an automatic on/off LED night light for door lock, based on infrared sensing technology. It has a built-in infrared sensor to detect the presence of person, and will turn on automatically when you approach the key hole. It will turn off automatically after you left for a few seconds. It is powered by a 1.5V AA battery (not included). Because it is an LED light and consumes little power, one battery will last a few months. Once installed, there is left no more fumbling by your door in the dark.