Where they actually differ
The most decisive specs, ranked by how much they matter — before the full spec table.
| Spec | Master & Dynamic - MW09 | Anker - Liberty 4 Pro |
|---|---|---|
| Battery — buds | 16 h | 10 h |
| Battery — with case | 48 h | 40 h |
| Driver size | 11 mm | 10.5 mm |
| Water resistance | IP57 | IPX4 |
| Weight per bud | 6 g | 5.6 g |
Between the MW09 and Liberty 4 Pro, the MW09 comes out ahead in battery — buds / battery — with case, while the Liberty 4 Pro wins on weight per bud. Overall, the MW09 scores 86.1 and the Liberty 4 Pro scores 81.6 on our Mars Score.
Which should you buy?
The MW09 edges ahead on the Mars Score (86.1 vs 81.6), but the 4.5-point gap is small enough that the right pick comes down to which spec advantages matter to you.
Pick the MW09 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 — buds, battery — with case, driver size, among others. The single most decisive one: Battery — buds — 60.00% more. 16 h vs 10 h.
Pick the Liberty 4 Pro if you care most about weight per bud. Its strongest claims are weight per bud. The single most decisive one: Weight per bud — 0.40 g less. 5.6 vs 6.
Both ship with comparable active noise cancellation, spatial audio, multipoint, so those specs do not separate the two — focus on the differences below.
Bottom line: there is no wrong answer here — match the spec advantages to how you actually use the product. The Mars Score parity says both are well-rounded; the differences are about trade-offs, not quality.
Which should you buy: Master & Dynamic - MW09 or Anker - Liberty 4 Pro?
Master & Dynamic - MW09 leads the current Mars Score by 4.5 points.The more useful decision is the trade-off behind that result: compare driver size, battery — buds, weight per bud against the way you will actually use the product.
Choose Master & Dynamic - MW09 if…
Master & Dynamic - MW09 has the measurable edge on battery life buds h, battery life case h, driver size mm.
Choose Anker - Liberty 4 Pro if…
Anker - Liberty 4 Pro has the measurable edge on weight per bud g.
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 Master & Dynamic - MW09 wins
- ▲Battery — buds — 60.00% more. 16 h vs 10 h.
- ▲Battery — with case — 20.00% more. 48 h vs 40 h.
- ▲Driver size — 4.76% more. 11 mm vs 10.5 mm.
- ▲Water resistance: IP57 (vs IPX4).
Why Anker - Liberty 4 Pro wins
- ▲Weight per bud — 0.40 g less. 5.6 vs 6.
Spec comparison
Design
| Spec | Master & Dynamic - MW09 | Anker - Liberty 4 Pro |
|---|---|---|
| Form factor | in-ear | in-ear |
| Weight per bud | 6 g | 5.6 glead |
| Water resistanceⓘ | IP57lead | IPX4 |
Audio
| Spec | Master & Dynamic - MW09 | Anker - Liberty 4 Pro |
|---|---|---|
| Driver sizeⓘ | 11 mmlead | 10.5 mm |
| Active noise cancellationⓘ | true | true |
| Transparency mode | true | true |
| Spatial audioⓘ | false | false |
Battery
| Spec | Master & Dynamic - MW09 | Anker - Liberty 4 Pro |
|---|---|---|
| Battery — buds | 16 hlead | 10 h |
| Battery — with case | 48 hlead | 40 h |
| Wireless case chargingⓘ | true | true |
Connectivity
| Spec | Master & Dynamic - MW09 | Anker - Liberty 4 Pro |
|---|---|---|
| Bluetoothⓘ | 5.4 | 5.4 |
| Codecsⓘ | aptX Lossless,aptX Adaptive,AAC,SBC | LDAC,AAC,SBC |
| Multipointⓘ | true | true |
| In-ear detection | true | true |
Frequently asked
Which has longer battery, MW09 or Liberty 4 Pro?+
MW09 lasts 16h per charge vs 10h.
Do MW09 or Liberty 4 Pro support multipoint?+
Both support multipoint pairing.
Which has ANC, MW09 or Liberty 4 Pro?+
Both models have active noise cancellation.