The ceiling mount DS939 PIR Detector provides a 21 m (70 ft) panoramic coverage pattern and can be used on ceilings as high as 7.6 m (25 ft). With three separate PIR sections that are fully adjustable, the DS939 provides coverage integrity at all mounting heights, plus the ability to customize the coverage for specific areas. The DS939 uses several patented processing techniques to provide excellent catch performance with freedom from false alarms.