Between the Phone (3a) Pro and OnePlus Open 2, the Phone (3a) Pro comes out ahead in front camera and weight, while the OnePlus Open 2 wins on antutu and wired charging. Overall, the Phone (3a) Pro scores 63.8 and the OnePlus Open 2 scores 74.5 on our Mars Score.
Which should you buy?
The OnePlus Open 2 is the clear pick on raw spec strength, leading by 10.7 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 Phone (3a) Pro if you photograph or shoot video regularly and want the better imaging pipeline of the two. The biggest gaps in its favor are front camera, weight.
Pick the OnePlus Open 2 if you push the hardware — gaming, on-device AI, heavy multitasking — and the extra compute headroom is worth the trade-offs. Its strongest claims are antutu, wired charging, ram, among others.
Both ship with comparable main camera, refresh rate, 5g support, so those specs don't separate the two — focus on the differences below.
Bottom line: the OnePlus Open 2 is the safer default. The other model is the right choice only when its specific advantages line up with your priorities.
Why Nothing - Phone (3a) Pro wins
- ▲Front camera — 56.25% more. 50 MP vs 32 MP.
- ▲Weight — 28.00 g less. 211 vs 239.
Why OnePlus Open 2 wins
- ▲AnTuTu — 215.29% more. 2680000 vs 850000.
- ▲Wired charging — 60.00% more. 80 W vs 50 W.
- ▲RAM — 33.33% more. 16 GB vs 12 GB.
- ▲Screen size — 18.17% more. 8.0 " vs 6.77 ".
- ▲Battery capacity — 14.00% more. 5700 mAh vs 5000 mAh.
- ▲Pixel density — 3.88% more. 402 ppi vs 387 ppi.
- ▲Water resistance: IP68 (vs IP64).
- ▲Promised OS updates: 4 (vs 3).
Spec comparison
Design
| Spec | Nothing - Phone (3a) Pro | OnePlus Open 2 |
|---|---|---|
| Weight | 211 glead | 239 g |
| Thickness | 8.4 mmlead | 11.7 mm |
| Water resistanceⓘ | IP64 | IP68lead |
| Form factor | bar | foldable_booklead |
Display
| Spec | Nothing - Phone (3a) Pro | OnePlus Open 2 |
|---|---|---|
| Screen sizeⓘ | 6.77 " | 8.0 "lead |
| Pixel densityⓘ | 387 ppi | 402 ppilead |
| Refresh rateⓘ | 120 Hz | 120 Hz |
| Peak brightnessⓘ | 3000 nits | 4500 nitslead |
Performance
Cameras
| Spec | Nothing - Phone (3a) Pro | OnePlus Open 2 |
|---|---|---|
| Main cameraⓘ | 50 MP | 50 MP |
| Front camera | 50 MPlead | 32 MP |
| Optical image stabilizationⓘ | true | true |
Battery
| Spec | Nothing - Phone (3a) Pro | OnePlus Open 2 |
|---|---|---|
| Battery capacity | 5000 mAh | 5700 mAhlead |
| Wired chargingⓘ | 50 W | 80 Wlead |
| Wireless chargingⓘ | 0 W | 50 Wlead |
Connectivity
| Spec | Nothing - Phone (3a) Pro | OnePlus Open 2 |
|---|---|---|
| 5G supportⓘ | true | true |
| Headphone jack | false | false |
| microSD slot | false | false |
Operating System
| Spec | Nothing - Phone (3a) Pro | OnePlus Open 2 |
|---|---|---|
| OS | Android | Android |
| Promised OS updates | 3 years | 4 yearslead |
Frequently asked
Which has better battery, Phone (3a) Pro or OnePlus Open 2?+
OnePlus Open 2 has 14.0% more battery — 5000 mAh vs 5700 mAh.
Which is lighter, Phone (3a) Pro or OnePlus Open 2?+
Phone (3a) Pro is 28g lighter — 211g vs 239g.
Is Phone (3a) Pro waterproof?+
Phone (3a) Pro has an IP64 rating.
Does OnePlus Open 2 support 5G?+
Yes, OnePlus Open 2 supports 5G.
Which has more RAM, Phone (3a) Pro or OnePlus Open 2?+
OnePlus Open 2 offers 16GB of RAM.
Which has a better camera, Phone (3a) Pro or OnePlus Open 2?+
OnePlus Open 2 has a 50 MP main camera vs 50 MP.
Spec-level deep dives
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