Evax 150W Charcoal Grey 8ZA. The Bosch Voice Evacuation systems and expansion panels provide a variety of options that can be easily added to an existing fire alarm control panel system for area of assembly applications and for high-rise voice evacuation not requiring firemens' phones. Choose up to 2000 W of audio amplifier power to meet your speaker power requirements. You can supervise multiple zones through your choice of zone splitters. The EVAX150 has one 50 W audio amplifier and one 100 W audio amplifier in a double-size enclosure.