Just spotted this carbon monoxide detector. Looks good for the price especially with 5 years guarantee.
The First Alert Carbon Monoxide Alarm will protect you in your home from the dangers of carbon monoxide by giving you an early warning from this potentially lethal threat. Carbon Monoxide (CO) is a colourless, odourless and tasteless poisonous gas produced by poorly fitted central heating systems, blocked flues or chimneys, open fireplaces and cooking appliances like gas hobs. This alarm is ideal for bedroom and living areas, making you aware quickly if levels of this dangerous gas rise, where in normal circumstances you may not notice.
The First Alert's loud 85dB alarm should wake you from even a deep sleep should you be in danger from carbon monoxide. However, it's handy hush button feature can be used to silence alarms if they become a nuisance. There is a test button included, allowing you to test your alarm on a weekly basis, as well as a low battery alert to remind you to replace the included batteries. Due to its battery powered operation, the alarm needs no installation, and wall fixings are included if you want to attach the alarm to your wall.
Carbon Monoxide Alarm
2 AA batteries