Aico's EI161E Ionisation Smoke Alarm has a Lithium back-up battery with a 10 year life. Best for fast-flaming fires (Papers, Clothing) Proven long life ionisation smike chamber BS EN 14604:2005 KM 522831
“Excellent replacement for previous Aico with 9V battery. Now don't have to worry about being woken up because battery has run flat. New detector slotted on to old base, but old base has yellowed somewhat. (New base is included).”