The Ei225EN is a Carbon Monoxide (CO) alarm powered by 230V AC mains power. The Ei225EN CO alarm uses a proven electrochemical cell type sensor which checks CO concentration every 50 seconds. All units are individually calibrated and tested in CO gas in order to ensure accuracy and they're covered by a lifetime (5 year) guarantee. The CO alarm is housed in a slimline casing and can be easily secured to a wall or ceiling, with all necessary fixings supplied. As well as being easy to install and maintain, the alarms have a vitally important memory feature which records if CO has been detected whilst the occupier was away. An easy to use Test/Hush button allows the user to check that the horn and electronics are working and to silence nuisance alarms.