Skroutz.eu

If you are in the Apple ecosystem, it's almost a one-way street.
There are several positive aspects, but one function that I found disappointing is that it essentially does not have a thermometer as we know it, at least the company has not unlocked its function and kept it for its big brother.
It does not provide wrist or ambient temperature.
It only measures the variation from your "baseline" temperature after wearing it for at least 5 nights...
A simple 60 euro Casio gives me accurate water/sea temperature on the spot.
It requires daily charging from the battery.
On the positive side, it has good accuracy in measurements at distances and underwater, it controls the mobile (iPhone) for taking photos and videos as a remote with a view of what the mobile sees, and it receives calls.