Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Amazfit - T-Rex 3 | Apple - Watch SE (2nd gen) |
|---|---|---|
| Battery life | 672 h | 18 h |
| Peak brightness | 2000 nits | 1000 nits |
| Weight | 68 g | 33 g |
| Display size | 1.5 " | 1.78 " |
| Water resistance | 10 ATM | 5 ATM |
| SpO2 | true | false |
Between the T-Rex 3 and Watch SE (2nd gen), the T-Rex 3 comes out ahead in battery life / peak brightness, while the Watch SE (2nd gen) wins on weight / display size. Overall, the T-Rex 3 scores 62.7 and the Watch SE (2nd gen) scores 55.9 on our Mars Score.
Which should you buy?
The T-Rex 3 edges ahead on the Mars Score (62.7 vs 55.9), but the 6.8-point gap is small enough that the right pick comes down to which spec advantages matter to you.
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, water resistance, among others. The single most decisive one: Battery life — 3633.33% more. 672 h vs 18 h.
Pick the Watch SE (2nd gen) if you carry the device everywhere and weight or thickness has been the deciding factor before. Its strongest claims are weight, display size, cellular. The single most decisive one: Weight — 35.00 g less. 33 vs 68.
Both ship with comparable ecg, so those specs do not 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.
Which should you buy: Amazfit - T-Rex 3 or Apple - Watch SE (2nd gen)?
Amazfit - T-Rex 3 leads the current Mars Score by 6.8 points.The more useful decision is the trade-off behind that result: compare display size, battery life against the way you will actually use the product.
Choose Amazfit - T-Rex 3 if…
Amazfit - T-Rex 3 has the measurable edge on battery life h, peak brightness nits, water resistance atm.
Choose Apple - Watch SE (2nd gen) if…
Apple - Watch SE (2nd gen) has the measurable edge on weight g, display size in, has cellular.
This is a structured comparison of the published catalog values. It is not a claim of identical real-world performance across every workload; use the linked spec drill-downs and methodology page to inspect the inputs.
Why Amazfit - T-Rex 3 wins
- ▲Battery life — 3633.33% more. 672 h vs 18 h.
- ▲Peak brightness — 100.00% more. 2000 nits vs 1000 nits.
- ▲Water resistance — 5.00 ATM more. 10 vs 5.
- ▲Has SpO2.
Why Apple - Watch SE (2nd gen) wins
- ▲Weight — 35.00 g less. 33 vs 68.
- ▲Display size — 18.67% more. 1.78 " vs 1.5 ".
- ▲Has Cellular.
Spec comparison
Design
| Spec | Amazfit - T-Rex 3 | Apple - Watch SE (2nd gen) |
|---|---|---|
| Case size | 48.5 mmlead | 44 mm |
| Weight | 68 g | 33 glead |
| Case material | polymer | aluminum |
| Water resistanceⓘ | 10 ATMlead | 5 ATM |
Display
| Spec | Amazfit - T-Rex 3 | Apple - Watch SE (2nd gen) |
|---|---|---|
| Display size | 1.5 " | 1.78 "lead |
| Always-on display | truelead | false |
| Peak brightnessⓘ | 2000 nitslead | 1000 nits |
Health & Fitness
| Spec | Amazfit - T-Rex 3 | Apple - Watch SE (2nd gen) |
|---|---|---|
| ECG | false | false |
| SpO2 | truelead | false |
| Temperature sensor | truelead | false |
| Sleep tracking | true | true |
| Blood pressure | false | false |
Battery & Connectivity
| Spec | Amazfit - T-Rex 3 | Apple - Watch SE (2nd gen) |
|---|---|---|
| Battery lifeⓘ | 672 hlead | 18 h |
| GPS | true | true |
| Cellular | false | truelead |
| NFC | false | truelead |
| OS | Zepp OSlead | watchOS |
Frequently asked
Which has longer battery life, T-Rex 3 or Watch SE (2nd gen)?+
T-Rex 3 lasts 672 hours vs 18 hours.
Do T-Rex 3 or Watch SE (2nd gen) support ECG?+
Neither supports ECG.
Which has cellular, T-Rex 3 or Watch SE (2nd gen)?+
Watch SE (2nd gen) offers a cellular variant; T-Rex 3 is Wi-Fi only.