I recently tested a wireless Zigbee siren to use with my home automation setup. Below are my impressions after a few months of real-world usage.

Image: Zigbee siren used in this review.
Pros
- If reception is good - at least 100 LQI, it works well - quite loud, although an industrial/AC powered siren is usually louder.
- Have a tamper button which will fire the alarm if removed without disarming it first (for instance in Zigbee2MQTT).
Cons
- If Zigbee connection brakes, the siren will not reconnect, it requires re-pairing. This is cumbersome especially if the siren is mounted in a high place.
- To click the pairing button need to unscrew the screws in the back, the screw are small and their threading will not last long.
- Occasionally, during paring, the alarm may trigger without any apparent reason (even when the tamper alarm is off).
- No battery level indication, at least not in Zigbee2MQTT.
- Water isolation looks decent so far, it survived the end of the winter and a few heavy rain showers.
Overall Rating
★★☆☆☆ 2 out of 5 stars — functional, but unreliable for long-term unattended use.
Related links
Zigbee siren prchase link (affiliate)