The S003KA motion activated alarm and chime will detect intruders through its passive infrared sensor (PRI).  The coverage area is 110 degrees horizontally and 20 degrees vertically with an approximately 30 foot range and can provide up to 800 square feet of indoor protection.   When motion is detected the built in 100 dB alarm sounds.  This unit will automatically reset itself when no further motion is detected.  The S003KA also has a chime mode that will sound a pleasant announcement chime when motion is detected and then reset itself.  The unit is powered by a 9 volt battery (not included). The unit measures six inches long by two and one-eight inches high by two and one-half inches wide.