The AARC-EVAC™ ARX92, ARX93 & ARX94 Standalone Wireless
Linked Emergency Alert Siren & Message Broadcast Units,
incorporates a Solar Power Supply, 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 part of a full standalone network of units to provide for redundancy if the PA system fails for any reason.