Switches and Lighting Controls, Occupancy Sensors, Adaptive TechnologyUltrasonic Ceiling Sensor, 2000 Square Feet Coverage, With Relay. "Install and Forget" operation. Auto-adjusting adaptive technology eliminates manual adjustments. Coverage 2000 sq. ft. (360°) with photocell and isolated relay, low voltage sensor. Digital, crystal controlled ultrasonic transmitter and receiver for coverage in each direction for superior sensing of movement. Green LED indicates ultrasonic detection. Minor motion detection. Office White ABS enclosure blends with ceiling tile. Relay to interface with auxiliary systems such as HVAC