It was my about 5th trial as I remembered to buying some IEM from KZ.
Judged to better than Xiaomi hybrid IEM, less bass but some exuberant - but still too much, ha - better for listening music in outdoor.
Around fitting on my ear was goor for me, but some people who wearing glass may not feels so comfort.
Just good to make an experience to take one more step to way of custom IEM from low cost under 20 USD.

I bought it about a week ago for gratify my curiosity in about 50 bucks !
Actually I don't like most of Audio-Technica's but it was first known single balanced armature driver included IEM before CKB70.
I just expected it could be better than SONY XBA-1,C10 or 1x~1xx series, and my expectation was right.
CKB50 is much better than SONY single driver IEMs in specially high frequency.
 
It just feels like more wisely expanded in end of high frequency to 20KHz than SONY single BA series.
Absolutely everything is better than SONY - assert ugly AUDIO ONLY BA whatever - single driver products.
 
I recommend good for under 50 USD, with T200 foamtips.

I was written personal review on my blog, you could read same review with images in my blog ( http://rageworx.ddns.net/index.php/kz-ate-review-in-a-month/ )
 
KZ-ATE is a popualr in ear headphone (or call it as canal earphone in some pacific nations,  I think it belongs to ‘auditory canal’) in Ali-Express and Amazon in low price but good sound. So I have bought this celebrituff (a word from mixing ‘celebrity’ and ‘stuff’) from Ali-Express. Surprisingly it taken a month for delivered to my home since ordered. Many sellers are using tracking not allowed or fake parcel numbers in Ali-Express. So I don’t recommend buy valuable something in Ali-Express.
KZ is known as Knowledge Zenith. Actually I don’t understand what it means, but they are using “KZ” model numbering for their stuffs: KZ-DT3, KZ-ED3, KZ-ED5, KZ-ATE ..
I bought 4 different stuffs from KZ official seller – name known as “He Yue” : KZ-DT3, KZ-ED3, KZ-ED9, KZ-ATE. And KZ-ATE is lastest product of them. Actually KZ-ATE was a brand new product when I ordered in their store.
KZ-ATE has two different colors in store: Silver and Dark-Transparency with options to mic controller or not. My order was two of dark-transparency and normal cable and mic controller.
Product finishing is just for its price. Speaker unit has little bigger than normal IEMs, actually fitting is not comfort. It provides 3 different sizes of silicon tips and plus a foam tip. Without foam tip, silicons are good to waste or use in other headphones. I used Ultimate Ears old silicon tip. Don’t hope you can use other silicon tips in this, KZ-ATE nozle is not kind of we knows before. Actually we don’t have many choice to use different tips.
 
Cable seems strong, looks special. But it’s all of cable. Cable surface has too much friction. It easily snarled and difficult to unsnarl it. Only one thing, plumb to speaker side is makes rounding fit to easy, that’s only one to good in cable, just all.
Sound is similar like ED3, ED9. Much like known as V-EQ, emphasized bass and treble. But decay of these  featured frequency of bass and treble makes breaking sound, specially complexed music. Maybe it is characteristic of dynamic driver based in ear headphones, but I don’t like to assent this, because some in ear headphones are not like this.
And one more, If you are using this headphone to your smartphone, and if it is kind of Android OS, you may understand sometimes auto voice app appears like pressed mic controller button even headphone has no mic controller ! It seems to problem of L-plug of headphone, but there’s no solution to solve this strange problem.
Conclusion? I just recommend if you want to have experience of new in ear headphone from China, and time to wait for a month or above. And not? don’t try. don’t waste your time and money. It’s just a piece of cheap one in USD 10 to 20.

I was bought in 10 monthes ago from AliExpress, and written a review in my blog ( refer to : http://rageworx.ddns.net/index.php/a-simple-review-of-earmax-e610/ )
 
Actually it was my curiosity for new dual BA unit - KNOWLES DTEC-30265, and soon I could know audio quality is not depends on name of Knowles.
 
Here my old review:
 
It is arrived in waited for long days. They simply described headphone specification in upper side of paper box (I can’t read chinese, so I paraphrased) :
    Model name: ER610
    Supported Frequency: 20 ~ 18000 Hz
    Impedance: 20 ohm.
    Sensitivity : 125 dB
    Cable length: 1.2 meters
 
Ok. I have continue to open a box.
There’s anti-static protection, it was sealed. Need to tear vinyl.
Retail box contains simply these:
    A Mic-controller-LESS headphone. NO mic, NO Controller. (I’ve been ordered mic controller)
    A plastic protective pouch.
    Two pairs of spare different size of silicon tips ( small and large )
    Impossible to readabled Chinese texted paper.
 
Shape of product
This headphone seems to made with aliminium alloy. Weight is really light, And contruction is not looks cheap, But some finishing is not clear like end point of metal cut of hole on each unit to cable protecting rubber.
Nozzle of each unit applied protective metal mash. Silicon tips may compatibles with Apple IEM. Softness is not like Apple’s, more harder. It may problem for some people has weak ear skin tissue. (but I guess they don’t like IEMs, before worry about them)
Cable quality is not same with KZ series even it looks like similar. Much better quality in fitting and strength.

Hearing
First impact of hearing is just simple. It’s not like TWFK series of Knowles. Similar to UE Super.Fi 4. Feels like heavy and darker because of less high frequency as like below table.
(you could see graph in my blog)
Definitely this is not for Hi-Fi reference audio as they written on the cover of box. Sound is too coarse, not optimized. Rather than better KZ-ED9 or KZ-ATE series to buy this in only tuned sound quality. Much far from HiFi reference.
 
Conclusion
This headphone contruction quality is good. But If you like to listen musics, don’t like to recommend this. I don’t believe it used dual BA of Knowles. Sound is too coarse like sands in wind. Middle range of frequency is inflated, but high is seems dead like zombie but it never be rised again.
 
Additional valuation
It’s not enough to believe used dual BA even try to listen in days. Expected crispy high frequency like others, but this has nothing like that. No advantage if you are finding featured in most of dual BA IEM.

 
I bought this stuff in online market.
And seller emphasized "WARM SOUND".
But my opinion is different. Warm? no, it's cold.
Compare with UE600 and this, you will know what I mean.
A151 has not enough bass to make sound going to warmmy
 
twisted cable and durable housing is good for price.
design is not a sense.
housing is little bit bigger than other BA transducer IEMs.
 

I compared this ultra sound TwinBA IEM with UE700.
UE700 and GH-ERC-DMS, both are dual/twin BA, but different tuned. 
 
audio source : iPod touch 4G 32GB and iPhone4G 32GB w/ ALAC or MP3 320KBps , 93~94dB normalized.
 
Outlook and packaging:
Oh, poor.
outfit made with plastic and inner is seems to urethane.
cable is really same as MEElec A151. ( shorter than A151, but same shape, material, connector )
S,M,L - Shure like silicon tips and carrying case. an adapter. it's all.
a license paper included.
 
Hearing:
It ... was impressed.
Bass is better than UE700. mid to high freq seems to same like UE700.
Specially high freq. hears crispy and sharp. really clear.
It's similar like T-PEOS H-100 on high freq. (bass is better than H-100)
 
Wearing:
There's nothing to explained how to fit on my ear. (even L,R not printed !)
But we know this type of IEM how to wear.
Wear cable to around earflap, insert  silicon tip into carnal side.
It is really comfort to me.
 
Value:
I don't care MSD whatever, payed totally around 80USD in Amazon Jp. (inc. delivery cost)
Economic choice !