Federal Signal's model 300GCX SelecTone® speaker amplifier is designed to produce tones, digital voice messages and live public address in harsh environments with high ambient noise levels. The rugged speaker cone and projector are constructed of spun aluminum. The amplification circuitry, tone module and gain control are contained in a housing constructed of die-cast aluminum. All surfaces are sealed with powder-coat paint. Dust- and moisture-proof gaskets provide protection from the elements. SelecTone® amplified speakers are used individually or as part of a plant wide emergency notification system. The model UTM Universal™ tone module, with 32 tones or the TM33 custom tone module is plugged into a single SelecTone® amplified speaker for stand-alone use or into a SelecTone® command unit for plant wide signaling. For plant wide signaling, a connector kit is installed into each SelecTone® amplified speaker and wired to a central controller, SelecTone® command unit or CommCenter® digital message center. Command units and CommCenter® broadcast tones, voice messages, melodies and live public address to an unlimited number of SelecTone® amplified speakers.