The 710-9LS is very loud and very bright sure to capture your attention asleep or awake.  This portable smoke detector is AC-powered, so you do not need an electrician to install it. It has all the same features and quality as the other Gentex smoke detector models, except with battery backup. Battery backup operates audible alarm only. This photoelectric single station smoke detector is designed to give reliable early warning of the presence of smoke where both audible and visual alarms are required.