In this video I test the Apple Watch Ultra siren. In short it fails.
Apple say the siren can be heard up to 180 metres away. They say:
86-decibel Siren. Sonic salvation. If you get lost or injured and need to attract attention, hold the Action button to activate a siren that can be heard up to 180 metres away
It can't. Please don't rely on it

Link to a detailed review of the Apple Watch Ultra here:
   • Apple Watch Ultra v. Garmin FR955: Is...  

WATCH

Manufacturer: Apple
Model: Watch Ultra
Colour: Titanium Case
Weight (body only as tested): 61.00g/2.15oz
Cost: $799 / €999 / £849 / AU$1,299
Purchased From: Apple
Location: Online
Date: 08 September 2022
www.apple.com

Manufacturer: Apple
Model: 49mm Ocean Band
Colour: Yellow
Weight (as tested): 35g/1.25oz
Cost: $99 / €99 / £99 / AU$149

EQUIPMENT:

Audio:
Rode Video Mic Pro+
Tascam DR60-DMKII

Video:
GoPro Hero 11

Editing:
Editing Software: Adobe Premiere Pro

SOUND:

All music from the YouTube Audio Library:

Intro and end music:
Goggles Extract Sound: Royale by Josh Lippi & The Overtimers

Goggles Identity by Unthink

Exterior Location: The Shelley Banks, Dublin, Ireland

Details accurate as per day of posting

Thanks for watching and reading

Contact: oldman@oldmanrunner.com