The InnovairFlex D2 2-wire photoelectric duct smoke detector features a pivoting housing that fits various applications: both square and rectangular footprints mount to round or rectangular duct work. This new duct smoke detector senses airflow speeds ranging from 100 to 4,000 feet per minute with proven System Sensor precision. The enhancements built into this model improve false alarm immunity (with plug-in sensor head); broaden operating temperature (-4°F to 158°F) and humidity (0 to 95 percent noncondensing) ranges; while simplifying installation and maintenance. These advance features can detect smoke even in the harshest duct applications. The new design provides more wiring space with an added ¾ inch conduit knockout. Numbers and labels for terminal designations are consistent with previous Innovair models. The new sampling tube can be clicked into position with one smooth motion from either the front or the back of the detector.