All versions of the Ei161 smoke alarm have now been discontinued but the original manufacturer Ei Electronics (known as Aico in the UK) have ensured that their new range of alarms is fully backward compatible with the Ei160 series that it replaces. The replacement optical smoke alarm is the ideal replacement for the Ei161. The new alarm can interlink with any Ei160 series alarms remaining in your system, and even fits onto your existing Ei160 base without the need for any rewiring. The new optical sensor technology is less susceptible to false alarms, making it suitable for use in a wider range of locations such as rooms adjacent to kitchens, hallways, landings, bedrooms, and living areas. This replacement alarm is supplied with an easichange tool making the replacement process as smooth as possible.