The Fire Angel SB1 optical smoke alarm is best at detecting slow smoulering fires & is less prone to nuisance alarms. The SB1 is powered by a 9V battery that is supplied with the alarm. 3 year warranty. The Fire Angel CO-9B carbon monoxide detector is suitable for wall mounting or left free standing as a portable device. The Fire Angel CO-9B is supplied as standard with 2 x AA batteries to power the alarm. 7 year warranty.