Features [CO & Smoke Combination Detector] With advanced electrochemical carbon monoxide sensor and a photoelectric sensor, the detection of CO and smoke are accurate. [Human Voice Warning Alarm] When dangerous smoke or CO concentration is detected, it will warn you with loud human voice sound. [LCD Display Screen] Can clearly indicate real-time carbon monoxide concentration in the surrounding air and remaining battery. [Battery Power Supply] Powered by 3 * 1.5V AA (not included), no need to charge, no messy wires, convenient to use. [Easy to Install] Comes with one bag of screws, easy to install the detector on walls of bedroom, living room, kitchen, etc. Specifications Color: Multicolor Material: ABS Detection Gas Type: CO, smoke Alarm Mode: Flash + loud alarm pattern Smoke Sensor Type: Photoelectric CO Sensor Type: Electrochemical Working Temperature: -10~60 Relative Humidity: 10~95%R.H. Smoke Sensitivity: 0.1%db/m~9.9%db/m CO Sensitivity: 000-999 PPM Alarm sound: 85dB (1 meter) Alarm Concentration: 50ppm: Screen light up, 150ppm human voice alarm Power Supply: 3 * 1.5V AA (not included) Product Size: 12.6 * 12.6 * 4cm/ 4.9 * 4.9 * 1.5inch Product Weight: 162g/ 5.7oz Note Batteries are not included. Package List 1 * Detector 1 * Bag of Screws 1 * User Manual