The E-960 series are easy-to-install extended range infrared detectors designed to provide reliable perimeter security both indoors and outdoors. Built-in laser beam alignment system speeds accurate, reliable positioning. Detection occurs when there is simultaneous breaking of 2 beams. The time interval used for detection is selectable: setting the interval longer will reduce false alarms from birds or falling leaves, etc., while setting it shorter will provide for detection of faster moving objects.