Technical Specifications: 1) Alarm Dimensions:3.9?dia., 1.6?ht. 2) Working Current : a)Static Current:?12μA b)Alarm Current: ?15mA 3) Operating Voltage: DC9V 4) Audio Alarm : 85 Db at 10 feet. 5) Temp Range :14°F( -10°C) to147°F( 60°C) 6) Humidity Range: ?95%RH?40±2°C? 7) Battery : 9V battery back-up for at least 1 year. 8) Protection area : 6 m high , 60 ?. 9) Latching alarm indicator remembers which unit initiated an alarm. 10) Smart sense system helps reduce unwanted alarms. 11) Single button test/Silence. 12) Perfect mount system : Gasketless base allows for easy installation & positioning. 13) Dust cover keeps alarm clean during construction. 14) Test button: electronically simulates smoke condition ,causing the unit to alarm. 15) Alarm reset: automatic when smoke clears . Press test/silence button to silence alarm manually. 16) Sensor: Photoelectric technology is more sensitive at detecting large particles which tend to be produced by smolding fires before bursting into flames.