The Strand Lighting 61327 Contact Power-Pack Ceiling Mount Occupancy Sensor is a multiple technology, occupancy-sensing low-voltage device that is designed for use with one Contact Power Pack System Relay Pack. An LED indicator illuminates when the sensor detects occupancy. Each unit provides automatic on / off. Up to 8 sensors can be used with each power pack. When mounted at a maximum height of 12’ (3.65 m), the standard Ceiling Occupancy Sensor detects occupancy in an area of more than 1,200 sq. ft with a minimum field of view that is equal to 360° and an axial range of 40’ (12.19 m).