CO SMOKE DETECTOR, Battery Chemistry Alkaline, Battery Location Back, Battery Locking Pin No, Battery Size AA, Communication Protocol Not Applicable, Compatible With Not Applicable, Detector Type Smoke/CO Detector, Features Hush Button, Includes Mount Bracket, Self Testing Components, Number of Tandem Detectors 18, Power Source Removable Battery, Sensor Type Electrochemical, Photoelectric, Visual Alert Type Red LED, Volume Level 85 dB @ 10 ft, No, Alarm Setting 70 ppm