The MDC-50L is a commercial grade low voltage ceiling mount sensor that operates lights using a combination of passive infrared (PIR) and ultrasonic technologies. The dual-technology sensor features a 360° field of view fresnel lens that provides up to 1600 sq.ft. of PIR coverage and 1000 sq.ft. of ultrasonic coverage. This ceiling mounted sensor operates lights ON/OFF based on occupancy and ambient light levels detected in the area. The occupancy sensor turns lights ON when motion is detected and OFF when no motion is detected for a pre-selected time delay. Ambient light level detection prevents the occupancy sensor from turning lights ON when the ambient light levels are sufficient. Both the time delay and light level settings can be easily adjusted. This ceiling sensor is compatible with either LED or fluorescent lights. The sensor is also compatible with 91245 momentary switch for optional vacancy mode and manual ON/OFF operation Note that power pack supply MPP-24 is required for the MDC-50L sensor to work. This ceiling mount motion sensor is ideal for use in offices, classrooms, warehouses and other commercial areas.