CPG Signals Model SPHX Powertone Explosion-proof Speaker is designed for use in hazardous locations. The unit produces a crisp, clear, high decibel tone/voice output on any 25 Vrms or 70 Vrms tone/voice audio system. Speaker cone and projector are of spun aluminum, the speaker driver and circuitry are contained in an explosion-proof housing. This speaker has a supervisory DC coupling capacitor and wattage taps from 0.5 to 15 watts. Our speaker is listed for indoor or outdoor use, is NEMA 3 rated, and is finished in red enamel. The PowerTone speaker is designed for connection to system supervised alarm notification circuits. The weatherproof corrosion-resistant surface-mount speaker is required.