Apple Watch Ultra

Display

 49mm case size

Flat sapphire front crystal with display edge

protection Certified IP6X dust resistant

 Tested to MIL-STD 810H

Customizable Action button

Always-On Retina display
Up to 2,000 nits brightness

Nearly 27% more screen area than Apple Watch SE

Water-resistant

Swimproof and recreational dive to 40 meters

EN13319 certification

Depth gauge with water temperature sensor

Oceanic+ app for use as a dive computer (Available on App Store)

Sensor

Blood Oxygen, High and low heart rate notifications, Cardio fitness notifications, Temperature sensing, Fall Detection, Crash Detection, High-g accelerometer, and Gyroscope.

GPS and Connectivity

International
emergency calling

Redesigned Compass app with waypoints and backtrack, Precision dual-frequency GPS, Always-on altimeter, And Mobile connectivity

Battery

 Up to 36 hours in normal use.

60 hours on low power setting.