Easy to Use: Unique design, small wireless portable and easy installation (screws included). Precise combined electro-optical sensor, universal high consistency and stability, moving or in the same place for this. Quick and loud danger alarm: Warning alarm when a dangerous level of carbon monoxide concentrations above 100 ppm is detected, the red LED flashes and a loud alarm sounds, a loud alarm of 85 decibels. Clear LED Display: Protect the family from carbon monoxide, with an optional 3-digit LED display, "err" on the LCD screen to indicate that the device is malfunctioning First start condition : Energy saving, powered by 3 x 1.5V AA batteries (included), the buzzer will make a "di" sound, the detector will start preheating, it will display 2 minutes counting when the detector is starting. Protection area of wide-range smoke detectors: When the height of the space is 6m-12m, the protection area of one detector is 80 square meters for general protection. The height of the space is