... years 4,Low battery signal 5,Sound:>85DB at1M Co alarm Power Supply: DC 9V battery operated,Lithium batterySensitivity Setting: ... life: >5 YearsDisplay range: 20-999PPMHush functionLow battery voltage alarmFault alarm indicateRecommended battery: Gold peak 1604A, Gold power G6F22Alarm sound: ≥85DB ... at 100cm at 3.4±0.5KHz pulsing alarm (The alarmPattern is 4 short beeps-followed by 5 seconds ...