Carbon monoxide alarm twin pack offers great value when buying two or more alarms., Carbon monoxide detector providing early warning of the presence of CO in your home through alarm & LED display, An internal power pack will power the alarm for 7 years in normal operating conditions, so there's no need to replace any batteries, A test & reset button makes weekly testing easy, Portable so can be taken on holiday or installed within the home, Kitemark certified to quality standard BS EN 50291-2001