Smoke Alarm, Battery Chemistry Not Applicable, Battery Location Not Applicable, Battery Locking Pin No, Battery Size Not Applicable, Communication Protocol Not Applicable, Compatible With 2 Wire Fire Alarm System, Detector Type Smoke Detector, Features Removable Detector Cover and Chamber, Built-In Remote Maintenance Signaling, Drift Compensation and Smoothing Algorithms, Thermal Sensor, Includes Mounting Base, Number of Tandem Detectors Not Applicable, Power Source Hardwired