The Skylink motion sensor protects your home by detecting movement inside house. Monitors your front or back yard and driveway, too. Designed to work with Skylink Security systems; notifies control panel of deluxe system (Item# 164287) or emergency dialer (Item# 17615, if installed) for standard system (Item# 164286). Battery Type: 9V, Battery Included: Yes, Application: Add-on sensor, Detections Motion (ft.): 40