Most open-ear headphones are designed around one idea: keep your ears uncovered while delivering enough sound for everyday listening. The Monster AC739 headset takes that concept in a slightly different direction. Instead of looking like a conventional pair of sports headphones, it combines an open-ear earclip design with a charging case styled more like a small handbag accessory.
That makes the AC739 interesting for people who want wireless audio without the sealed feeling of traditional in-ear earbuds. It also brings several useful specifications into a very small package, including Bluetooth 6.0, 10mm drivers, AAC/SBC support, directional sound transmission, and up to 20 hours of claimed playback with the charging case.
The AC739 is part of a growing category of open-ear headphones, a format designed for listeners who want audio without completely sealing the ear canal.
The important question, however, is not simply how many features the AC739 lists. It is whether the combination makes sense for everyday listening, commuting, calls, and exercise.
Monster AC739 at a Glance
| Feature | Monster AC739 |
|---|---|
| Design | Open-ear earclip |
| Bluetooth | Bluetooth 6.0 |
| Driver | 10mm |
| Audio codecs | AAC / SBC |
| Impedance | 16Ω |
| Frequency response | 20Hz–20kHz |
| Earbud battery | 30mAh each |
| Charging case | 300mAh |
| Claimed playback | Up to 5 hours per charge / 20 hours with case |
| Charging time | About 1 hour |
| Transmission distance | Up to 10m |
| Weight | About 43g listed product weight |
| Microphone | Yes |
| Colors | Black, Orange, Pink |
The specifications above come from the current Banggood product listing.
The AC739 Is More About Wearing Style Than Another Pair of TWS Earbuds
The first thing that separates the AC739 from ordinary wireless earbuds is the way it sits on the ear.
Rather than entering the ear canal, the earbuds use a C-shaped earclip structure. This leaves the ear canal open while keeping the speakers positioned close to the ears. Banggood lists the individual earbuds at approximately 3.7g and describes the design as lightweight and pressure-conscious.
That distinction matters.
Traditional in-ear earbuds can provide a strong seal, but some people dislike the plugged-in sensation or simply do not want something sitting inside their ears for extended periods. An open-ear design approaches the problem from the opposite direction: comfort and environmental awareness become part of the listening experience.
For walking, commuting, desk work, or casual outdoor use, that can be a more natural arrangement.
It also means the AC739 should not be judged by exactly the same expectations as a sealed in-ear model. Open-ear headphones generally prioritize a different balance between sound delivery, comfort, and awareness of the surrounding environment.
A Charging Case That Looks Like an Accessory
Monster has given the AC739 another unusual visual feature: the charging case is designed to resemble a small quilted handbag.
That is not merely a cosmetic specification. The case changes how the product is positioned. Many wireless earbuds are intentionally anonymous, with a small plastic charging case designed to disappear into a pocket. The AC739 instead treats the case as part of the product’s visual identity.
For users who care about the appearance of their accessories, this could be more appealing than another generic black charging case.
The available colors are listed as black, orange, and pink, giving the AC739 a more fashion-oriented identity than many conventional sports earbuds.
Bluetooth 6.0: Useful, but Don’t Judge the Headset by the Number Alone
The AC739 uses Bluetooth 6.0 and supports HSP, HFP, A2DP, and AVRCP profiles. The listing also specifies a transmission distance of up to 10 meters.
If you are comparing different wireless audio designs, our guide to Bluetooth headphones can provide additional context on features such as connectivity, comfort, and everyday use.
Bluetooth version numbers can easily become marketing shorthand, but the practical question is whether the connection remains dependable during everyday use.
Monster’s product description emphasizes faster connectivity, improved interference resistance, and low-latency transmission. Those are manufacturer claims rather than independent test results, so they should be treated accordingly.
For normal smartphone listening, the more relevant benefit is compatibility with common Bluetooth audio functions rather than simply having “Bluetooth 6.0” printed on the specification sheet.
10mm Drivers Give the AC739 Enough Hardware for Everyday Music
The AC739 uses 10mm speakers and supports both AAC and SBC audio codecs. Its listed frequency response is 20Hz–20kHz, while impedance is 16Ω.
A 10mm driver does not automatically determine whether headphones sound good, because tuning, acoustic positioning, enclosure design, and DSP all affect the final result.
Here, the driver is working with an open-ear design rather than a sealed ear canal. That is an important distinction.
Monster describes the AC739 as delivering a broad 360-degree surround-style stereo presentation. The company also emphasizes its audio tuning and directional transmission system.
In practical terms, buyers should think of the AC739 as an open listening device, not a replacement for noise-isolating in-ear monitors. It is aimed at keeping the ears uncovered while placing audio close enough to the listener to remain useful for music and calls.
Directional Audio Is One of Its More Interesting Features
The AC739 also promotes directional sound transmission, with the product listing claiming up to 98% reduction in sound leakage.
That figure should be regarded as a manufacturer claim rather than an independently verified measurement.
Nevertheless, the underlying idea is important for open-ear headphones. Once the ear canal is no longer sealed, controlling where the sound travels becomes more challenging. Directional audio attempts to focus more of the acoustic output toward the listener instead of dispersing it broadly into the surrounding space.
This is particularly relevant for people who want an open-ear design but do not want their audio to become excessively noticeable to nearby people.
Actual leakage will still depend on volume, environment, fit, and listening content, so buyers should not interpret the advertised percentage as a guarantee of complete privacy.
Battery Life: 5 Hours From the Earbuds, 20 Hours With the Case
Battery capacity is another area where the AC739 takes a straightforward approach.
Each earbud has a listed 30mAh battery, while the charging case contains a 300mAh battery. Monster/Banggood specifies up to 5 hours of playback from the earbuds alone and up to 20 hours when the charging case is included. Charging is listed at approximately one hour.
That makes the AC739 better suited to repeated short listening sessions than to people who expect extremely long single-session playback.
For example, a user might listen during a commute, put the earbuds back into the case during work, and recharge them before another session later in the day.
As with other wireless audio products, the advertised runtime should be considered a maximum claim. Actual battery life can change depending on volume, connection conditions, calls, and other usage factors.
Open-Ear Design Makes the AC739 More Interesting for Outdoor Use
The open-ear format is arguably the main reason to consider the AC739.
Because the earbuds do not completely block the ear canal, users can remain more aware of surrounding sounds while listening. That can be useful when walking around a city, working at a desk, or exercising in environments where hearing what is happening nearby is important.
However, open-ear headphones are not a substitute for paying attention to traffic or other hazards. For activities around roads or other potentially dangerous environments, users should prioritize situational awareness rather than relying on any headphone design.
The product listing also describes the AC739 as having a waterproof design, but it does not provide a clear IP rating in the specifications shown.
For that reason, it would be better not to treat the AC739 as fully waterproof or suitable for swimming unless Monster provides a specific water-resistance rating.
Calls Are Part of the Package
The AC739 includes a microphone and supports the standard HFP and HSP Bluetooth profiles listed for voice communication.
That gives the headphones a broader role than simple music playback. They can also function as a hands-free audio device for compatible phones and other Bluetooth hardware.
Still, microphone quality is difficult to judge from specifications alone. Factors such as microphone placement, background-noise processing, wind handling, and software tuning can have a much larger effect on call quality than the presence of a microphone itself.
Since the current listing does not provide independent microphone measurements or customer review data, call performance should be considered an area to evaluate after real-world use rather than a guaranteed strength.
Who Is the Monster AC739 For?
The AC739 makes the most sense for a particular type of listener.
It is worth considering if you:
- Prefer open-ear headphones to in-ear earbuds
- Want an earclip design rather than traditional stems
- Spend time walking, commuting, or working while listening to audio
- Want to keep your ears uncovered
- Prefer a more fashion-oriented charging case
- Want Bluetooth 6.0 connectivity
- Need a microphone for calls
- Want up to 20 hours of combined claimed playback
On the other hand, it may not be the right format for someone whose priority is strong passive isolation, powerful sealed bass, or a highly controlled listening environment.
That is not necessarily a weakness of the AC739. It is simply the trade-off created by its open-ear architecture.
Monster AC739 vs Traditional In-Ear Earbuds
The biggest difference can be summarized quite simply.
A traditional in-ear earbud puts the emphasis on sealing the ear and controlling the sound environment.
The AC739 puts more emphasis on keeping the ear open while positioning audio close to it.
That changes the priorities.
If you frequently listen in noisy environments and want maximum isolation, a sealed design may make more sense. If you dislike the feeling of silicone tips or want greater awareness of your surroundings, the AC739’s earclip approach may be more attractive.
This is why the AC739 should not be evaluated only by its driver size or Bluetooth version. Its defining feature is the listening philosophy behind the design.
Final Thoughts
Monster AC739 is an unusual open-ear Bluetooth headset that combines practical wireless-audio specifications with a deliberately fashion-focused design.
Its strongest points on paper are the open-ear C-clip construction, 3.7g claimed earbud weight, Bluetooth 6.0, 10mm drivers, AAC/SBC support, directional audio technology, microphone, and up to 20 hours of claimed total playback.
The more interesting part, however, is how those features work together. The AC739 is not trying to be another anonymous pair of TWS earbuds. Its handbag-style charging case and earclip construction give it a distinct identity, while the open-ear format targets users who want audio without completely sealing their ears.
There is one important limitation to keep in mind: the current Banggood listing shows no customer reviews, so there is not enough independent feedback yet to make firm claims about long-term comfort, microphone performance, sound tuning, or durability.
For that reason, the AC739 is best viewed as an interesting open-ear option based on its published specifications rather than as a product with independently verified performance.
If your priority is a combination of comfortable open-ear listening, compact earclips, and a distinctive accessory-style charging case, the Monster AC739 has a clear point of difference from conventional wireless earbuds.