Kidde Mains Carbon Monoxide Alarm with digital display and non-replaceable, sealed-in Lithium cell for seven years of continuous protection, that can be interconnected with up to 17 other Kidde and FIREX mains alarms. Ideal for new builds, major refurbishments of existing properties or complete re-wiring projects and can be wall or ceiling mounted and requires installation by a professionally qualified electrician. Complies with UK Building Regulations for new housing and associated standards (BS EN 50292 code of practice).