The Fire-Lite D365PL intelligent non-relay photoelectric duct smoke detector and DNRW watertight non-relay photoelectric duct smoke detector feature a pivoting housing that fits both square and rectangular footprints capable of mounting to a round or rectangular duct.These units sense smoke in the most challenging conditions, operating in airflow speeds of 100 to 4,000 feet per minute (0.5 ? 20.32 m/s), temperatures of -4?F ? 158?F (-20?C ?70?C), and a humidity range of 0 ? 93 percent (non-condensing).Main FeaturesCover tamper signalIncreased wiring space with a newly added 3/4" conduit knockoutEasily accessible code wheels on sensor head (included with D365PL)Clear cover for convenient visual inspection (D365PL only)Remote testing capability