Hardwired heat alarm with battery backup is designed for areas not suitable for smoke alarms, such as garages, kitchens, or laundry rooms. Rate-of-rise thermistor sensing triggers the 85 dB alarm if the temperature reaches 135 °F or rises more than 15 °F in one minute, helping detect dangerous heat quickly. Unit interconnects with compatible First Alert/BRK alarms and includes a 9V backup battery. | First Alert | | Hard-Wired w/Battery Back-up Ionization Heat Alarm 1 pk | Best Buy