A simple way to protect your home. Rigorously tested and simple to install, these FireAngel smoke alarms are powered by a 10-year lithium battery - easily fit them to a wall or ceiling for instant peace of mind.\nThe optical sensor works by ''seeing'' smoke as it enters the alarm - perfect for detecting slow-burning fires with thick white smoke. A red operating light flashes approximately every 40 seconds to let you know the smoke detectors are powered.\nWhen the time comes to replace these optical fire alarms, a low battery warning will let you know. Want to keep it quiet for the night? A sleep-easy function allows you to silence the low battery chirp for eight hours, without compromising on protection.\n\n• Optical sensor - fast response to slow-burning fires\n• Loud 85dB(A) alarm alerts you of danger\n• Flashing red operating light to confirm alarm is powered\n• Simple testing with large central push button\n• Quiet test function for discreet testing at a lower volume\n• Suitable for caravans and leisure accommodation vehicles\n• Easy wall or ceiling installation with fixings supplied\n• Sleek fit - 118.1mm diameter and 31.5mm projection\n• Non-interlinkable - two standalone battery smoke alarms\n• Sealed-for-life lithium battery with 10-year lifespan\n• Low battery warning with sleep-easy function\n• Certified to EN 14604:2005+AC:2008