Increase your peace of mind at home by making sure intruders don t go undetected. The Skylink Wireless Security System Door/Window Sensor monitors your home entrances and alerts you when a door or window is opened. Keep your property safe; keep your family safe. When the door or window is opened contact is broken between the sensor and the magnet and the sensor signals the receiver to alert you. Note: Requires a compatible Skylink receiver. FEATURES: Protects doors windows and other entrances. Sends a signal to your Control Panel or Dialer when the entrance is opened. Works with Skylink Security System and Emergency Dialer. Add on as many magnetic contacts as needed. CONTENTS: Sensor Battery.