The Ei650 Optical Alarm is best for detecting slow, smouldering fires commonly produced by electrical fires or sofas and is less likely to react to cooking smells if fitted in the hallway next to the kitchen. · · · 10 year Lithium battery powered · · Easy to fit – twist on base and multi-fixings · · Standalone unit · · Battery-powered with a sealed-in lithium battery · · Dimensions: Product – 115mm(D) x 50mm(H) · · 5 year guarantee · · Alarm fault warnings · · Aesthetically pleasing, compact design · · Aico Ei650. 10-Year life