SkylinkHome ID-318 Wireless Water Resistant Motion Sensor Automatic  Light Activated  Energy Savings Transmitter for Indoor and Outdoor  Home Automation Save energy and wirelessly activate a light when motion is detected by turning lights on/off automatically. Adjustable countdown timer can be set to turn on lights when it is dark with 5, 30 and 60 minute timer options. Automated motion activated lighting is an ideal home improvement for energy savings in areas with low foot traffic. Built in photo cell will also help in energy savings by only allowing lights to turn on when the ambient light level is dark enough for the light to be needed. Up to 500 feet long operating range (from Skylink HomeControl receivers) Motion detecting range up to 40 feet with sensitivity setting option.