4 Packs, 2 in 1, Smoke and Carbon Monoxide Detector, Smoke Detector Carbon Monoxide Detector Combo,85db Alarm, Digital Display, with Battery, Easy to InstallBrand: TJTFJS Color: white 91304 Features: 2 in 1 DetectionThe product uses high sensitivity photoelectric sensor to detect smoke and high stability electrochemical co sensor to detect carbon monoxide. Alarm Sensitivity: When the smoke or CO concentration reaches the alarm sensitivity, the red light will light up and the alarm sound will reach 85 decibels. Working State: When the concentration is normal, the screen turns off to achieve power saving