Apple Watch Ultra 4 - 49mm - Black

Yes, it is water-resistant up to 100 meters, suitable for swimming and recreational diving.

While it has cellular capabilities to make calls and texts independently, an iPhone is required for initial setup and firmware updates.

It offers up to 45 hours of Max Extended Workout tracking on a single charge.

Yes, it uses heart rate variability (HRV) and daily readiness scores to provide insights into your body's stress and recovery levels.

The titanium case is highly durable and resistant to corrosion, though surface scratches can still occur depending on the impact.

The Apple Watch Ultra 4 features a large 49mm display designed for readability in bright outdoor conditions.

Ensure you are outdoors with a clear view of the sky. Check that 'Precise Location' is enabled for the Watch app in your iPhone settings.

Check if high-drain features like 'Always-On' display or frequent background app refreshes are enabled; consider using 'Low Power Mode' during non-critical hours.

Restart both devices, ensure Bluetooth is toggled on, and verify that your iPhone is updated to the latest compatible iOS version.