Photoelectric Sensor Smoke Detector Depth (In.) 2 1/2 in Height (In.) 5 in Length (In.) 7 3/4 in Ambient Temp Limits (F) -4 Degrees to 158 Degrees F Air Velocity (FPM) 100 to 4000 fpm Humidity Range ( Percent RH) 0 to 95 Percent RH Number Required 1 Standards FM UL Includes Duct Smoke Detector Sensor For Use With Mfr No D4P120 RTS2 DST Sampling Tubes