Between the T-Rex 3 and Watch Ultimate, the T-Rex 3 comes out ahead in battery life and peak brightness, while the Watch Ultimate wins on ecg. Overall, the T-Rex 3 scores 79.7 and the Watch Ultimate scores 64.5 on our Mars Score.
Which should you buy?
The T-Rex 3 is the clear pick on raw spec strength, leading by 15.2 points on the Mars Score. The margin is wide enough that the underdog only makes sense if its individual strengths line up with what you specifically need.
Pick the T-Rex 3 if your top frustration with your current device is running out of charge before the day ends — endurance is the lead spec here. The biggest gaps in its favor are battery life, peak brightness, weight.
Pick the Watch Ultimate if you care most about ecg. Its strongest claims are ecg.
Both ship with comparable display size, cellular, spo2, so those specs don't separate the two — focus on the differences below.
Bottom line: the T-Rex 3 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Amazfit - T-Rex 3 wins
- ▲Battery life — 100.00% more. 672 h vs 336 h.
- ▲Peak brightness — 100.00% more. 2000 nits vs 1000 nits.
- ▲Weight — 8.00 g less. 68 vs 76.
Why Huawei - Watch Ultimate wins
- ▲Has ECG.
Spec comparison
Design
| Spec | Amazfit - T-Rex 3 | Huawei - Watch Ultimate |
|---|---|---|
| Case size | 48.5 mm | 48.5 mm |
| Weight | 68 glead | 76 g |
| Case material | polymer | titanium |
| Water resistanceⓘ | 10 ATM | 10 ATM |
Display
| Spec | Amazfit - T-Rex 3 | Huawei - Watch Ultimate |
|---|---|---|
| Display size | 1.5 " | 1.5 " |
| Always-on display | true | true |
| Peak brightnessⓘ | 2000 nitslead | 1000 nits |
Health & Fitness
| Spec | Amazfit - T-Rex 3 | Huawei - Watch Ultimate |
|---|---|---|
| ECG | false | truelead |
| SpO2 | true | true |
| Temperature sensor | true | true |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Amazfit - T-Rex 3 | Huawei - Watch Ultimate |
|---|---|---|
| Battery life | 672 hlead | 336 h |
| GPS | true | true |
| Cellular | false | false |
| NFC | false | truelead |
| OS | Zepp OSlead | HarmonyOS |
Frequently asked
Which has longer battery life, T-Rex 3 or Watch Ultimate?+
T-Rex 3 lasts 672h vs 336h.
Do T-Rex 3 or Watch Ultimate support ECG?+
Watch Ultimate supports ECG; T-Rex 3 does not.
Which has cellular, T-Rex 3 or Watch Ultimate?+
Neither offers cellular.
Spec-level deep dives
More from the same brands
vsMars is reader-supported. When you buy through links on our site, we may earn an affiliate commission at no extra cost to you. Learn more.