10 Year Digital Display Carbon Monoxide Alarm - Kidde K5DCO - £18.95 inc VAT - Safelincs - Kidde approved reseller
Kidde Nighthawk Carbon Monoxide Detector & Propane, Natural & Explosive Gas Detector, AC-Plug-in with Battery Backup, Digital Display, White & Smoke Detector, Battery Powered with Test Button - Amazon.com