The Kidde KF10 is a mains powered smoke alarm with a 9V back-up battery with the capability of interlinking with other Firex KF series alarms via hardwire. The ionisation-based sensor in the KF10 has been discontinued by Kidde and the ideal alternative is the KF20. The KF20 uses all the same features of the KF10, however adopts the newer optical sensor technology using the same base plate and connector. This ensures the smooth transition from one alarm to the next without the need for an electrician. Optical smoke detection is much less susceptible to false alarms from everyday fumes such as cooking vapours and natural humidity. This makes them ideal for installation in hallways, bedrooms, landings and living areas, including those rooms adjacent to kitchens, but not within them.