The FireAngel SO-601 optical smoke alarm with toast proof sensing technology, operated by a 9V alkaline battery has now been discontinued. The replacement FireAngel alarm is designed to be a straightforward replacement and use the base plate from its previous model without the requirement for any DIY or decorating. The new alarm is powered by a sealed 10-year battery, with no requirement to change batteries for the entire 10-year lifespan of the alarm. Activated by attaching to the base plate, this optical smoke alarm is designed to detect slow, smouldering fires especially those maintained by soft furnishings making it ideal for installation in bedrooms and living rooms.