Smoke Alarm Battery Chemistry Alkaline Battery Location Back Battery Locking Pin Yes Battery Size 9V Communication Protocol Not Applicable Compatible With Not Applicable Detector Type Smoke Detector Features Alarm Memory Includes 9V Battery Number of Tandem Detectors 24 Power Source Sealed Battery Sensor Type Ionization Visual Alert Type Green LED Red LED Volume Level 85 dB @ 10 ft Alert Type Sound Battery Backup No Detects Smoke