Federal Signal's patented Global Series models were designed with modularity in mind. While they are completely functional as stand-alone devices in both flameproof "Ex d" and increased safety "Ex de" assemblies, 2-module configurations are also available to serve applications that require more than one signal. Global Series devices are designed with a non-metallic housing construction. The Dual Signal assembly allows two audible or visual. Global Series devices to be combined as one complete assembly, with a common increased safety "Ex de" field wiring chamber that greatly simplifies the installation and wiring of two signals. The Dual Signal can be surface-mounted or mounted with an optional ratchet-adjustable stainless steel mounting U-bracket. Either of the devices can be wired to function independently or in tandem. Two like devices can also be combined to support a redundant alerting system, simplifying the installation of A/B redundant systems.