Apple Watch Ultra 4 / Amazfit T-Rex 3 (48 mm)

Apple Watch Ultra 4: A3579; 49 mm natural titanium; translucent gray Ocean Band

Amazfit T-Rex 3 (48 mm): 48.5 mm case, 1.5-inch AMOLED; Onyx (black), Lava and Gray colours. The T-Rex 3 Pro, T-Rex 2 and the T-Rex Ultra 2 are separate models.

SpecificationApple Watch Ultra 4Amazfit T-Rex 3 (48 mm)
Release year20262024
Announcement / availability9 / 18 September 2026 Apple—
CaseGrade 5 titanium; sapphire front crystal Apple—
Size49 × 44 × 12 mm Apple—
WeightNatural titanium case 63 g Apple68.3 g (without strap) Amazfit
DisplayLTPO3 OLED; 422 × 514 Apple1.5-inch AMOLED, 480 × 480 pixels, 322 ppi; Gorilla Glass touchscreen

There is also a night display mode.

Amazfit
Brightness1 nit minimum; 3000 nits peak Apple—
ChipS11; dual-core 64-bit Apple—
Storage64 GB Apple—
Health sensorsElectrical/optical heart; blood oxygen; temperature Apple—
Outdoor sensorsDepth, water temperature, compass, altimeter Apple—
PositioningPrecision dual-frequency GNSS Apple—
WirelessWi-Fi 4, 2.4/5 GHz; Bluetooth 5.3; UWB Apple—
CellularA3579: 5G RedCap and LTE Apple—
Manufacturer battery testUp to 50 hours normal use; 84 in Low Power Mode Apple—
ChargingAbout 45 minutes to 80% Apple—
Water / dust100 m rating; IP6X Apple—
Diving limitRecreational diving to 40 m Apple—
Phone compatibilityiPhone 11 / SE 2 or later; iOS 27+ Apple—
Case and strap—48.5 × 48.5 × 13.75 mm; stainless-steel bezel, polymer middle frame; 4 buttons; 22 mm liquid-silicone strap for 145–210 mm wrists

The 22 mm strap is a standard width and can be swapped.

Amazfit
Water and diving—10 ATM; freediving to 45 metres (147 ft) certified to EN 13319, ISO 6425 and GB/T 18828

10 ATM means withstanding the pressure of 100 metres of still water for up to 10 minutes. Breath-hold training and testing are downloaded through the Zepp app.

Amazfit
Battery—700 mAh; 27 days typical, 13 days heavy use, 40 days battery saver, 81 days clock mode; 42 hours in accuracy GPS mode, 72 hours power-saving GPS, 180 hours maximum GPS mode

A full charge takes about 3 hours; a magnetic charging base is in the box but no USB-C cable. Low-temperature mode gives 28 hours with GPS on and 32 days with it off. The maximum GPS mode works only in hiking and climbing modes.

Amazfit
Positioning and navigation—Dual-band and single-band modes; 6 satellite systems; offline maps, turn-by-turn directions, route import, back-to-start and off-route alerts

Dual-band positioning receives two frequencies from the satellites to reduce drift from reflected signals among tall buildings and dense trees; it uses more battery. Automatic mode switches settings based on signal strength.

Amazfit
Sensors—BioTracker 6.0 PPG biometric sensor; accelerometer, gyroscope, magnetometer, barometric altimeter, ambient light, temperature sensor

The watch offers an altitude assistant, storm alerts, compass, sunrise/sunset and tide information, and prompts for blood-oxygen readings at high altitude.

Amazfit
Connectivity—Bluetooth 5.2 (BLE), 2.4 GHz Wi-Fi; microphone; music storage

Wi-Fi is used to download software updates without the phone. The watch shows incoming calls but cannot take Bluetooth calls; quick reply works on Android only.

Amazfit
Sports and health—170+ sports modes (177 listed); recognition of 25 strength and 8 sports movements; 24-hour heart rate, blood oxygen and stress; sleep stages; PAI; Zepp Coach

Chest straps, running/cycling power meters and cycling speed/cadence sensors can be paired; data can be exported to apps such as Strava, komoot and Apple Health.

Amazfit
Compatibility—Android 7.0 and later, iOS 14.0 and later; Zepp app Amazfit