Chamberlain CWA2000 Motion Alert System, 30 ft, 120 deg Detection

This convenient safety and security system uses passive infrared (PIR) to alert with a unique light and sound pattern to identify which sensor has been triggered. Includes one year warranty, one battery/AC-powered base receiver and one sensor (CWPIR), additional CWPIR sensors sold separately. No wiring is required and the base unit uses the included AC adapter or AA batteries, which will last up to 2 years.