Provides a warning when the concentration of CO is too high. CO is odourless and can be deadly. Supplied with a replaceable 3-year battery. Make sure you're alerted when there's too high a concentration of carbon monoxide in your home by fitting this Smartwares CO alarm. Carbon monoxide is odourless and can be deadly - that's why it's so important to regularly test and replace your detectors and alarms. * 3-year replaceable battery - sensor lifetime of 10 years * 85db alarm - sounds when CO concentration is too high * Test button - easy to carry out regular alarm checks * Low battery indicator - alerts you if battery needs replacing * Indoor use - suitable for areas of 20m² to 40m² * Easy to fit - place near combustion devices with a few screws.