System Sensor i3 sounder and relay smoke detectors apply the guiding principles of installation ease, intelligence, and instant inspection in a series of specialty conventional devices. Throughout the i3 series, installation is simple with its installer-friendly base and plug-in design. The base accommodates a broad range of back box and direct mounting options and provides ample space for pre-wiring the device. To complete the installation, the i3 detector plugs into its base with a simple Stop-Drop 'N Lock action.