This BG mains-powered smoke and heat alarm is ideal for use in loft spaces, and has a wireless feature for remote testing and silencing when paired with the SDMREM remote (sold separately). The 35m (100m open air) range allows you to mount the remote in a convenient place whilst remaining in range of the alarm. Connect with other BG interconnecting alarms for whole-home coverage. A 10-year lithium backup battery ensures protection during power cuts. Easy to install with colour coded terminals.