Amazfit T-Rex Dual Solar vs Apple Watch Ultra 4
The T-Rex Dual Solar puts much more emphasis on battery life, offline navigation and extended outdoor use, with solar charging helping stretch its already long runtime. Apple Watch Ultra 4 is the more smartwatch-focused option, with ECG, readiness, higher-frequency heart rate and HRV measurements, deeper iPhone integration and a much broader app ecosystem, but its quoted outdoor workout battery life tops out at 45 hours.
Full comparison
The full record
76 specifications across 6 areas, with 37 genuine differences.
1. Design & display Mixed
Fact
Amazfit T-Rex Dual Solar
Apple Watch Ultra 4
Release date
2026-09-22
2026-09-18
Physical size
51.4 mm diameter; 16.9 mm thick including heart-rate sensor; 14.5 mm excluding sensor
49 x 44 x 12 mm
Weight
69 g without strap
63.0 g (Natural), 63.1 g (Black)
Material
Grade 5 titanium bezel and buttons; fiber-reinforced polymer middle frame; Grade 5 titanium and glass-ceramic back
Grade 5 titanium case
Water resistance
10 ATM; recreational diving to 50 m
10 ATM; IP6X; MIL-STD 810H; recreational scuba diving to 40 m
Color options
Basalt Black
Natural Titanium, Black Titanium
Display type
AMOLED
Always-On Retina LTPO3 wide-angle OLED
Display size
1.32 inch
49 mm case
Display resolution
466 x 466 pixels (353 ppi)
422 x 514 pixels
Display brightness
Up to 3,000 nits
Up to 3,000 nits
Display protection
Sapphire glass
Flat sapphire crystal display
2. Battery & charging Amazfit T-Rex Dual Solar
Fact
Amazfit T-Rex Dual Solar
Apple Watch Ultra 4
Battery
Rechargeable battery; 660 mAh
Rechargeable lithium-ion battery
Battery life
Up to 25 days typical; 13 days heavy use; up to 34 days with front solar / 51 days with rear solar (3 h/day at 50,000 lux); up to 41 hours accurate GPS; Outdoor Extreme up to 40 days / 180 days with continuous rear solar at 50,000 lux
Up to 50 hours normal use; up to 84 hours in Low Power Mode; up to 18 hours outdoor workout; up to 25 hours Extended Workout; up to 45 hours Max Extended Workout
Charging
Magnetic charging head; dual-sided solar charging
USB-C magnetic fast charging; up to 80% in about 45 minutes
3. Sensors & positioning Mixed
Fact
Amazfit T-Rex Dual Solar
Apple Watch Ultra 4
GNSS type
Built-in dual-band GNSS
Built-in dual-band GNSS
GPS
Yes
Yes
GALILEO
Yes
Yes
GLONASS
Yes
No
QZSS
Yes
Yes
Beidou
Yes
Yes
Accelerometer
Yes
Yes
Gyroscope
Yes
Yes
Barometric altimeter
Yes
Yes
Compass
Yes
Yes
Ambient light sensor
Yes
Yes
Optical heart rate
Yes
Yes (always-on optical heart sensor; high-frequency background tracking)
Electrical heart rate
No
Yes
SpO2
Yes
Yes
Temperature
Yes
Yes
Galvanic skin response
No
No
Microphone
Yes
Yes
Speakers
Yes
Yes
Vibration motor
Yes
Yes
4. Health & activity Apple Watch Ultra 4
Fact
Amazfit T-Rex Dual Solar
Apple Watch Ultra 4
Steps
Yes
Yes
Distance
Yes
Yes
Calories burned
Yes
Yes
Floors
Yes
Yes
Sports tracking
180+ sports modes
Yes
Sleep
Yes
Yes
Heart rate
Yes
Yes
HRV
Yes
Yes (Up to 24x more frequent than Ultra 3)
Stress
Yes
No
Blood oxygen
Yes
Yes
Respiration rate
No
Yes
Skin temperature
Yes
Yes
ECG
No
Yes
Blood pressure
No
Hypertension notifications (no direct blood-pressure measurement)
Body composition
No
No
Glucose
No
No
Hydration level
No
No
UV exposure
No
No
Calorie intake
No
No
Hyperglycemia risk assessment
No
No
Arterial stiffness detection
No
No
Pulse wave arrhythmia analysis
No
Yes
5. Smart features Apple Watch Ultra 4
Fact
Amazfit T-Rex Dual Solar
Apple Watch Ultra 4
Smartphone compatibility
Android 8.0+ and iOS 17.0+
iPhone 11 or later or iPhone SE (2nd generation or later) with iOS 27 or later
Operating system at launch
Zepp OS 6
watchOS 27
Storage
26 GB available for maps, music, apps and data
64 GB
Bluetooth
Yes (5.2)
Yes (5.3)
Wi-Fi
Yes (2.4 GHz)
Yes (Wi-Fi 4 / 802.11n, 2.4/5 GHz)
NFC / connected pay
Yes (Zepp Pay, region-dependent)
Yes (Apple Pay)
UWB
No
Yes (2nd-generation UWB)
Cellular
No
Yes (5G RedCap and LTE on supported regional models)
Smartphone notifications
Yes
Yes
Bluetooth calling
Yes
Yes (standalone on cellular models; via paired iPhone otherwise)
Smartphone music control
Yes
Yes
On-board music storage
Yes
Yes
Voice assistant
Zepp Flow
Siri AI powered by Apple Intelligence
6. Navigation & safety Apple Watch Ultra 4
Fact
Amazfit T-Rex Dual Solar
Apple Watch Ultra 4
Maps
Yes (base, contour and ski-resort maps)
Yes
Offline maps
Yes
Yes
Navigation
Yes (turn-by-turn, POI display, route planning and waypoint navigation)
Yes
Emergency SOS
No
Yes
Satellite SOS
No
Yes
Fall detection
No
Yes
LED flashlight
Yes
No
Diving
Yes (recreational diving to 50 m)
Yes