Carbon monoxide, or CO, is a poisonous gas emitted from household items that are defective, and as a result are burning fuel incompletely. Common sources of CO include ovens, boilers, BBQ's, open and solid fuel fires, gas or paraffin heaters and blocked or broken chimneys and flues. Carbon monoxide cannot be smelt, tasted or seen, and can be deadly - the only way to be alerted to CO is with an audible CO alarm. FireAngel design their CO detectors in-house and rigorously test them to ensure the highest standard of protection for your family and home. They're also third party certified, tested and Kitemark Approved by BSI. Suitable for homes in England, Wales, NI and Scotland. Features: Rigorously tested in-house and third party approved and certified to Kitemark standards The CO sensor will detect, and provide a warning to, low levels of carbon monoxide, and will provide a ventilate alert as this increases Press the test button once for a complete alarm test with a quieter audible alert