Carbon Monoxide Alarm Battery Chemistry Lithium Battery Location Back Battery Locking Pin No Battery Size 3V Communication Protocol Not Applicable Compatible With Not Applicable Detector Type CO Detector Features Night Light Includes 3V Battery Number of Tandem Detectors Not Applicable Power Source Sealed Battery Sensor Type Electrochemical Visual Alert Type Digital Display Volume Level 85 dB @ 10 ft Accuracy +/-30 Percent (CO) Alarm Setting 30 ppm Alert Type Sound