Features: [CO and Smoke Combo Detector] With advanced electrochemical carbon monoxide sensor and photoelectric sensor, CO and smoke detection is accurate. [Flashing and Loud Alarm Pattern Warning] When dangerous concentration of smoke or CO is detected, it will warn you with LED flashes and loud alarm sound. [LED Display Screen] Can clearly show the real-time carbon monoxide concentration in the surrounding air. [Battery Power Supply] Powered by 2 * AAA (not included), no need to charge, no messy wires, convenient to use. [Easy to Install] Comes with a bag of screws, easy to install the detector on the walls of bedroom, living room, kitchen, etc. Specifications: Color: White Material: ABS Detection Gas Type: CO, Smoke Alarm Mode: Flash + Loud Alarm Sound CO Sensor Type: Electrochemical Working Temperature: -10~60 Relative Humidity: 10~95%RH CO Sensitivity: 000-999PPM Alarm Sound: ≥75dB(1 meter) Alarm Concentration: 50ppm: the screen lights up, 150ppm human voice alarm Power Supply: DC