This carbon monoxide detector features electrochemical sensing technology and photoelectric smoke sensor, optimized to detect larger smoke particles produced by smoldering fires. With an LCD display, the alarm clearly indicates real-time carbon monoxide concentrations, remaining battery life, and working status. It's easy to install with a mounting bracket, requires no hardwiring, and sounds an 80dB alarm when levels begin to rise. Battery-operated, this detector is a convenient and essential safety device for any home. Features 1. Carbon Monoxide Detector: Features electrochemical Carbon Monoxide sensing technology and photoelectric smoke sensor optimized to detect larger smoke particles produced by smoldering fires; helps minimize the number of false alarms. 2. Test button: press it for a few seconds to give an audible alarm indicating that the alarm is normal. 3. LCD Display: Clearly indicates real-time carbon monoxide concentration in the surrounding air as well as the remaining battery life, and working status of the alarm. 4. Easy Install and Use: The alarm can easily install with mounting bracket. No hardwired anymore, very convenient to install at home or bedroom-wall. 5. A loud 80-decibel alarm sounds when Carbon Monoxide, and Smoke levels begin to rise. Power supply: 3 AA batteries (Not Included Battery). Specification Material: ABS Color: White Size: 11 x 11 x 4 cm Weight: 100 g, 200 g Battery: 3 AA Batteries(Not Include) Working temperature: -20 C ~ +50 C Alarm decibel 80dB Package Include: 1 Carbon Detector or 2 Carbon Detectors