The AARC-EVAC™ ARX82-W, ARX83-W & ARX84-W Standalone Wireless
Linked Emergency Alert Siren & Message Broadcast Units, incorporates an
in-built Battery Backup UPS. They are fully self-contained making them ideal for
use in locations where there is no existing PA system, or to cover areas not
serviced by a PA system or as a full standalone network of units to provide for
redundancy if the PA system fails for any reason.