SpectrAlert Advance selectable-output horns, strobes and horn/strobes arerich with features guaranteed to cut installation times and maximize profits. The SpectrAlert Advance series of notification appliances is designed to simplify your installations, with features such as: plug in designs, instant feedback messages to ensure correct installation of individual devices, and eleven field-selectable candela settings for wall and ceiling strobes and horn/strobes. More specifically, when installing Advance products, first attach a universal mounting plate to a four-inch square, four-inch octagon or double-gang junction box. The two wire mounting plate attaches to a single-gang junction box.