The Federal Consumer Product Safety Commission recommends that every home be equipped with at least one UL Listed carbon monoxide (CO) alarm mounted near sleeping areas. According to the CPSC Chairperson, Carbon monoxide detectors are as important to home safety as smoke detectors. The NIGHTHAWK displays a red alarm light and emits a continuous piercing 85 decibel alarm whenever it detects dangerous levels of carbon monoxide. The Test/Reset button allows for the immediate silencing of the alarm. This AC direct plug model operates on house current; has a battery backup for added protection during a power failure, and there is no costly sensor replacement. When all is well, a green power-on light silently assures the unit is on, checking carbon monoxide levels. The sensor has a 5 year warranty. The CPSC recommends only alarms that meet Underwriters Laboratory Standard 2034, such as NIGHTHAWK carbon monoxide alarms. This unit is UL and ULC Listed.