Easy, fast, wireless installation: infrared sensor detects movement and sends a signal to the receiver. Chose from 38 ringtones with bright LED light. Wall Mount Sensor. Wireless Receiver Plug-in: The portable wireless receiver plug-in plugs into any standard outlet. The sensor uses 3 AAA batteries (not included). Delay between detection motion sensor alerts is configurable from 15 seconds to 30 seconds, just place the sensor at the entrance to your driveway and the receiver inside your home. Range of up to 328 feet (100 meters) between receiver and transmitter allows you to place it a good distance from the car to notify you of the arrival and departure of family members, unwanted guests or lawyers, or all visitors to your home or business. Ideal for front doors, window frames, walkways, hallways, and anywhere in the house you want to be alerted to movement. Also great for alerting business owners who work in the back, or out of sight, to customers entering their store. Note?: