Easy To Use: Unique design small wireless portable and easy installation(screws included). Precise combo electro optical sensor, high universal consistency and stability, move, or in the same place for that.^Quick And Loud Danger Alarm: Alarm warning when a dangerous level of the carbon monoxide gas concentrations more then 100PPm is detected the red led will flashes and a loud alarm pattern will sound loud 85 decibel alarm.^Clear LED Display: Protect the family from carbon monoxide, with 3 digits LED displayer is optional, 'err' on the lcd to indicate the unit is malfunctioning^First Start Condition : Energy saving operated by 3 x 1.5v AA battery operated/powered ( included), the buzzer will make a sound"di", the detector starting preheating, it will display 2 minutes counting wehn the detector is in starting-up.^Wide Range Smoke Detectors Protection Area: When sapce height is from 6m to 12m, the protection area of one detector is 80 square meters for the general protection. Space height is 6m, protection area will be 60 square meters when you go out travel.Combination smoke detector/carbon monoxide alarm detects two threats; Photoelectric sensor detects smoke while minimizing false alarms.