ag TWS04K - Black, Tuned by final

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ag TWS04K - Black​

ag TWS04K Black is tuned by the Japanese high-end audio brand, final, promising high-fidelity sound quality and can easily be considered as the best wireless solution for true audiophiles.

Who is ag?
ag is a brand established by final Inc. which also owns the Japanese audio brand, final.

Inspired by the old Japanese word "arigatakimono", the brand name ag has the meaning of one of a kind or appreciation.

By utilizing the experience and knowledge cultivated through contract development and manufacturing for major brands, the core of ag is to create exquisite products at affordable prices.

  • Sound tuned by final, premium Hi-Fi sound quality
  • aptX Compatible for stable connection and good sound quality
  • 180H ultra-long battery life
  • 2600mAH capacity mobile battery function
  • IPX7 Waterproof
  • Award Winning final's exclusive Type E ear tips for True Wireless
  • Comfort and stable with sleek and light design

Communication System: Bluetooth 5.0
Playback Frequency Band: 20Hz-20000Hz
Supported Codec: SBC, AAC, Qualcomm aptX
Audio Profiles: A2DP, AVRCP, HSP, HFP
Continuous Music Playback Time: SBC, AAC : Up to 9 hours, aptX : Up to 6 hours (Up to 180 hours with case)
Charging Time: Earphones: 2 hours / Case: 4 hours
Battery Capacity: Earphone 45 mAh / Case 2600 mAh
Accessories: Charging case, final TYPE E Truly Wireless Exclusive Edition ear tips in 5 sizes, USB type C charging cable

Price: USD129.99
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Latest reviews


Headphoneus Supremus
Pros: Sound - Tuning and Quality
Build quality and fit - final E tips (for TWS) included
Excellent Bluetooth quality / AptX supported
Very good battery time on earphones / Very high on case. Case works as portable battery
Review – ag TWS04K Black

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  • Communication Format: Bluetooth 5.0
  • Chipset: Qualcomm QCC3020
  • Frequency Response: 20Hz~20kHz
  • Supported Codecs: SBC, AAC, Qualcomm aptX
  • Supported Profiles: A2DP, AVRCP, HSP, HFP
  • Continuous Music Playback Time: SBC, AAC: Up to 9 hours, AptX: Up to 6 hours. Up to 180 hours with case.
  • Charging Time: Earphones: 2 hours / Case: 4 hours
  • Battery Capacity: Earphone 45 mAh / Case 2600 mAh
  • Accessories: Charging case, final TYPE E Truly Wireless Exclusive Edition ear tips in 5 sizes, USB type C charging cable
  • Water Resistance rating: IPX7

Price: U$ 130.

Available from ag Amazon store.

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About ag

The TWS04K Black I’ve received directly from final Inc. for review is the original Japanese version where the info and manual are all in Japanese. The international English version has been released already. The box and contents are the same and like many other products from final, the TWS04K arrives in a nicely designed box with a magnetic closure from its right side. The earphones are arranged in a thick foam material along with the charging carry case, and inside the small box there are a charging USB Type-C cable and extra ear tips. The tips are a new version of the final E series tips made for true-wireless, softer, shorter and with a wider bore than the standard E tips, and arrive in the 5 sizes, from SS to LL.

Do note that there are two different versions of the TWS04K, Black and White, and they should differ in their sound tuning and/or quality. The following impressions are based on the Black only.


The ag TWS04K Black has a standard design compared to various true-wireless earphones I tried. While the main earpieces are made of plastic, they don’t look cheap and feel robust and durable, yet lightweight. In addition they are IPX7 rated, so in theory should bear the rainy winter and hot summer days. The shape is all curved with zero sharp edges on it and smoothly finished. Considering the single dynamic driver and all the BT tech inside, they are of standard size, not particularly compact but not large, either. There is a LED indicator placed in the center of the MFB and a microphone just next to the button. The nozzle has a normal IEM width and length, unlike many TWS earphones which are shorter or narrower, so the TWS04K should fit easier and can be used with a larger variety of ear tips. However, I’ve settled with the included final E tips for true-wireless, which are softer and have a wider bore than the regular E tips. Incidentally, the fit is easier and it is quicker to achieve a proper seal. They are fairly comfortable without having a particular ‘ergonomic’ shape and isolation is about average. Not as high as the Jays m-Seven or even not as good as the ADV Model X, but still better than Hifiman TWS800 or M&D MW07.

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The charging case is a bit on the large size but still light. Made of sturdy plastic with a very nice added layer of synthetic leather pattern that gives a more sleek and premium look to it. Not really needed, but a nice touch, nonetheless. The earphones are held strongly by the magnetic surface inside. There is only one single small LED on the outside that will indicate both the earphones charging level and case battery, depending on the light color. As an extra feature the case holds a strong 2600mAh battery that not only provides a much extended recharging cycle for the earphones themselves, but also doubles as mobile battery for other devices through its Type-C charging port.

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The multifunctional button can be used to control the music playback, volume and phone calls, and even to start Siri and Google Assistant (if supported) – see table. The button is a bit hard to press and result uncomfortable when making continuous multiple operations pushing the whole earphones towards the ear. The volume level can get loud enough, tough the adjustment is not too accurate with a sharp jump from one step to the other. The button functions are still not the most logical to me; the right side is to skip to the next track but lower the sound volume, and vice versa for the left side.

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Battery and Wireless performance

Battery performance is very good, among the highest I’ve tried on TWS sets. The maximum time will depend on the BT codec used, longer on SBC/AAC, while short but of better quality on aptX. While the TWS04K is more simplistic and may not offer any special features like active noise-cancellation or ambient mode, the wireless connectivity is just excellent. It connects to the source very quickly and never drops or cuts off the sound.


Getting into the sound, I’m glad to report that the ag TWS04K-B delivers a very enjoyable sound and in high quality for what a True-wireless can reach, compared to similarly priced and even more expensive competitors. I had already tried several of the final IEMs, from the E4000 up to the current A8000 flagship, and while all of them presented a rather different sound there wasn’t any I could dislike. The TWS04K is advertised as having “clear vocals with sufficient bass”, and I found the description to be quite accurate. In fact, final has really nailed the tuning on the TWS04K. While for wired earphones I may often prefer the best balance possible, when it gets to TWS I can consider a more flavored sound as we are already giving up on best technical capabilities due to the total wireless limitations. And having a comfortable fit and isolation is also very important.

Overall, the 04K has a more midrange focused sound, a low-end that well accompanies it and clear yet forgiving treble. Obviously, calling the bass “sufficient” will be very subjective. Personally, I find it quite balanced between quantity and quality. It has a pleasant boost on the mid-bass area that is still comfortable; strikes well according to the music track solid, punchy and deep, and well defined when needed, but never overwhelming. Better tuned than the darker sounding m-Seven and Model X, which I quite liked, and more refined than the pricier MW07. It is still different than the dynamic driver based final IEMs like the E4000, E5000 or hybrid B1, which all have a more pronounced bass response, thicker, stronger but also more fun and fairly more extended not having the wireless limitations. But as it is, the TWS04K works just right for everyday on-the-go use.

The midrange is more forward than neutral. With a sense of warmth and extra body complementing the low-end fullness. I already mentioned on some previous (wired) final IEMs, that despite their different tuning, the midrange was always well tuned. And so it is on the TWS04K for a true-wireless model. The texture is almost spot on; not too thick but not lean either, maintaining a really good sense of transparency. Vocals are particularly good, though favoring upper vocals a bit more (maybe suiting more the Japanese rock/pop genres where even male voices are a bit more higher-pitched). Surprisingly, there is no sibilance or at least it is very rare.

Treble is more energetic on its lower area, whereas the upper-treble rolls-off a bit (not an uncommon trait on TWS). It remains fairly smooth all the way and so far has the best ‘air’ and most natural timbre among true-wireless earphones. Treble quantity is not too abundant but complements the mids and lows; much more comfortable and natural than the TWS600 and more correct than the TWS800. The level of detail is very competent for the price and the soundstage while nothing especially wide, sounds more open with good right and left channels separation.


Jays m-Seven & ADV Model X+

The m-Seven and Model X are quite similar in sound tuning and quality with a darker signature and strongly focused on the lower frequencies. The bass is much more dense and impactful with greater mid-bass emphasis and bloat. Lower midrange is thicker and more congested even towards the upper mids. Highs are laid-back (more so on the m-Seven) and much more limited in extension. The TWS04K is more refined and layered, accurate and faster in bass but still fun enough. Midrange is much more forward, clear and transparent and has a more balanced treble presence with more air and higher detail.

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Hifiman TWS600 & TWS800

The TWS600 sound’s rather neutral from lows to mids and then boosted at its treble. I used to consider it as a detail oriented TWS in-ear, with shy bass and lean and clear midrange. The ag’s 04K is much more enjoyable, fuller in sound and despite not being as bright as the TWS600, it sounds more coherent and balanced. The higher treble presence on TWS600 does not translate as ‘better’; in fact, the TWS04K has even better detail and more natural timbre, whereas the TWS600 is kind of artificial. TWS800 is more balanced, in a similar way to that of the TWS04K but not as rich. The TWS800 has more of a ‘safe’ sound tuning. It has more weight when compared to the TWS600 but still not as impactful as the 04K on the lows and not as forward on the midrange, either. The treble on the TWS800 is something in the middle between the 600 and 04K in quantity, and a bit better in quality than the 600’s, but the 04K wins being more natural, extended and airy. I strongly prefer the TWS04K over the TWS600, and if found at the same price it has the higher value. Also would take it over the twice expensive TWS800, be it for fit, battery, BT performance, and ultimately, sound quality.

Master&Dynamic MW07+

The MW07 has a warm and rich sound, not as dark and bassy as the m-Seven or Model X, but still more impactful and thicker than the TWS04K. The bass is slower on the MW07, more prominent on the mid-bass area and less balanced overall. The TWS04K extends a bit better and is more linear. Midrange, while rich on the MW07, is not as forward and lacks the clarity, detail and separation the TWS04K offers. Treble is well complementing the overall sound on the MW07, though the TWS04K is more sparkly and energetic.

final x EVA 2020

Last comparison will be with another final TWS set, the made-for-true-otaku EVA2020. Aside from the distinctive design on the EVA2020, the main shape is very similar to the TWS04K Black; same size, weight and angled nozzle and width, and button functions. Will get into more details on a future EVA2020 review, but in a brief sound comparison these two ‘tuned by final’ TWS sets are really different in tuning. The EVA2020 has very strong bass focus; greater extension and rumble, more sub-bass presence and mid-bass power than can be easily overwhelming. It has a fairly darker signature where the midrange is more distant compared to the mids-forward TWS04K Black; the EVA2020 is heavier and on the low-mids, while upper-mids are laid-back with smooth, inoffensive treble response. The overall detail is actually not below than the 04K, but due its specific presentation the micro details are not as easy to pick. Soundstage is still a bit wider on the EVA2020, while the 04K is airier and presents a more accurate imaging. Clearly, in terms of overall value the winner is the ag TWS04K at a more affordable price, whereas the EVA2020 adds the unique design shape and original voices from the famous anime series.

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While the ag TWS04K Black is the first product I try from the final / ag brand, there is a lot to like about it. Build quality for a true-wireless is very decent, with an easy fit and the good exclusive final E tips. The battery time is very good, and the case working as a portable battery is a high advantage. Moreover, the Bluetooth quality is excellent and the best I tried so far on any TWS set. As for sound, I won’t hide it, the tuning definitely suits my tastes for what I tend to prefer on a True Wireless set – the frequency response, the balance, the fun factor, and it still shows very good technical capabilities compared to the several TWS I tried. The ag TWS04K is a new favorite true-wireless set.
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So this is an identical copy of the Lypertek Pureplay Z3. Wonder if they just borrowed the Shells? I also wonder if it is the same driver. This happens too often


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