Samsung Galaxy Watch Ultra (47 mm, 2024) / Amazfit T-Rex 3 (48 mm)

Samsung Galaxy Watch Ultra (47 mm, 2024): Galaxy Watch Ultra 47 mm (SM-L705, LTE); Titanium Gray, Titanium White and Titanium Silver at launch. The Galaxy Watch Ultra (2025), sold with a Titanium Blue option, is a later release of the same design whose specifications are not applied to this record; the Galaxy Watch Ultra2 and Galaxy Watch7 are separate models.

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.

SpecificationSamsung Galaxy Watch Ultra (47 mm, 2024)Amazfit T-Rex 3 (48 mm)
Release year20242024
Display1.5-inch (37.3 mm) 480 × 480 Super AMOLED; full-colour Always On Display; Sapphire Crystal

Samsung quotes 3,000 nits peak brightness for readability in sunlight. Night Mode faces switch to red tones in the dark.

Samsung		1.5-inch AMOLED, 480 × 480 pixels, 322 ppi; Gorilla Glass touchscreen

There is also a night display mode.

Amazfit
Case47.1 × 47.4 × 12.1 mm; 60.5 g; Titanium Grade 4 frame

According to Samsung, Grade 4 titanium is used only on the front and back cover areas of the metal frame; the rest of the frame is a mix of plastic and Grade 2 titanium.

Samsung		—
ProcessorExynos W1000 (5 core, 3 nm) Samsung—
Memory and storage2 GB memory + 32 GB storage

This figure is for the 2024 launch model; the Galaxy Watch Ultra (2025) version may differ.

Samsung		—
Battery and charging590 mAh (typical); up to 100 hours in Power Saving and 48 hours in Exercise Power Saving; WPC-based fast wireless charging

In Exercise Power Saving some features, such as network and Bluetooth connections, may be unavailable. Durations come from Samsung’s internal lab tests.

Samsung		—
Operating systemWear OS 5 (Powered by Samsung) with One UI 6 Watch at launch; One UI 8 Watch update released in July 2025

The One UI 8 Watch update brought Watch8 features such as Running Coach, Vascular Load and Antioxidant Index.

Samsung		—
SensorsSamsung BioActive Sensor (Optical Bio-signal sensor + Electrical Heart Signal + Bioelectrical Impedance Analysis), temperature, accelerometer, barometer, gyro, geomagnetic, light sensor

Health features are for general wellness, not diagnosis; some measurements depend on the market and the paired phone.

Samsung		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
ConnectivityLTE, Bluetooth 5.3, Wi‑Fi 2.4+5 GHz, NFC, GPS (L1+L5) / Glonass / Beidou / Galileo

L1+L5 dual-frequency GPS uses two satellite signals to improve location accuracy among tall buildings and trees.

Samsung		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
Durability10ATM + IP68, MIL-STD-810H; ocean swimming; operation from −20 to 55 °C; altitude from 500 m below sea level to 9,000 m

10ATM means 10 minutes at 100 metres under ISO 22810; Samsung says the watch is not suitable for high-pressure water or scuba diving. IP68 covers 1.5 metres of fresh water for 30 minutes.

Samsung		—
Buttons and safetyTwo buttons + orange Quick Button; Emergency Siren

The Quick Button can be mapped to start and control workouts; holding it sounds the emergency siren.

Samsung		—
Phone compatibilityAndroid 11 or higher with more than 1.5 GB of memory Samsung—
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
Weight—68.3 g (without strap) 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
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