Audible and visual device notifies guests and employees of an emergency. Designed to flash at the same rate when used with a compatible synchronization source (not included). Also features a selectable candela output with a switch on the side of the device; setting is visible even after installation. Fits standard single gang electrical boxes; no extension ring or trim plate required. Signals are hardwired from a control panel (sold separately). UL 1971 Listed for the hearing impaired.