KZ AZ09 Bluetooth 5.4 Module Wireless Waterproof Ear Hook Extra Long Battery Life Bluetooth Cable for ​KZ ZST/ZSTX/ZS10/AS06/AS10/BA10/ZSR/ES4 (B pin)

I'll give you a quick TLDR: They are good, buy them. They have latency on HD audio which sucks for watching video, but if you turn of HD audio they still sound great and the latency goes away. The rest of this is specifics about the the audio. Honestly, these sound amazing and I don't really feel the lack of lossless audio. The AAC audio is very high definition and it doesn't really sound different than one of my bluetooth DACs with lossless paired with the same iems. It seems that the digital amplification circuitry is very good a similar to a proper dac. No "hiss" at low audio levels and no crunchy fade in's from silence to audio. Reading some of the other reviews people have mentioned that the pairing audio is super loud. I would agree with that, but in my case I never ran into disconnections so I never deal with it. I think if you also experience solid connectivity that shouldn't be a problem, but your success will vary. I will say that I am really please with how stable the connection is as a huge guy. This is going to sound dumb, but I'm used to headphones cutting out if they don't have really good bluetooth because bluetooth signal has a hard time transmitting through flesh. Being 6'5 and 350lbs, I'd say 1 out of 4 bluetooth headphones I use cut out randomly at times because of this issue. These didn't have that issue with either headphone. One tip I will give people with these is that, if you are dealing with serious latency while using them to watch things like youtube, it seems like these headphones are slow on the decoding of the HD Audio. They sound genuinely fine even without HD audio on, so if you are using them with Youtube a lot you might turn off HD audio. Oh, and the case is 10/10. Seriously, I have a case for my IEM's and it's fairly compact, but given the nature of the IEM's I use the most, they are just chonky. It's hard to make anything that isn't thick that can safely store them. This has just enough room and the rounded edges makes it about comfortable as a case for these IEM's can be. It makes me want to 3d print a similar case, but with a little extra room for a cable.

Another great purchase to write about! I work around our property every weekend and being a music lover I always have ear buds in so I can listen to tunes while I work. The problem is apparently my ears are misshapen in some way that makes every ear bud I've tried not seat correctly so the buds fall out of my ear. Anyone who constantly has to readjust or push their earbuds in can feel me on that point. I wanted a quality ear bud that fit securely and wouldn't come loose as I worked - and this product didn't disappoint. I will say that being Chinese made, it has some funny quirks - it sounds like the lady announcing that the device has connected says "Connectate" instead of "Connected". I don't really care about that though - all I care is that the sound is good quality and the buds stay firmly in my ear. This product did both very well and I'm loving not having to take my buds out and reseat them every 5 mins. I'm using a after product foam type ear piece - you can squish it down tight, put it in your ear, and it will expand to fit perfectly. Battery life has been great for the time I've had these (about 6 months). I'll work around our 7 acre property for 6-7 hours without having to charge and it still has juice left if I forget to charge them. This also has an option to be used as a corded ear bud as well, which I did find useful since I travel a lot and use headphones with a plug while flying to watch movies or listen to music. Now I have the best of both worlds. From a cost/value perspective you can't beat the price and they do seem to be of good quality. I would recommend this to anyone looking for a versatile set of music buds, that stay put in your ear and block out unwanted noise, keep their charge for 7+ hours, and are easy to pair to your phone/tablet or computer. I'd definitely buy them again.

I still have the set and charging case and it still works fine. Best pair of earphones I've ever had before. Sound is great as long as they are fitted in your ear correctly. I use them when I mow the yard mainly, that's how good they are. Though they will slip loose and let sound in as I get sweat on my head. They don't last all day on a single charge either but they can go for a couple of hours before needing to be put back in the charge case if your using the BT mode. I also have the wires so I don't have to use the Bluetooth/Battery adapters unless I want to. The units pair with any Bluetooth device, so I can use them with my phone, or either of my computers easily. I got the earphones with wires for $20 and the BT and battery for $30 so a little over 50 dollars for all the components. Considering how expensive name brand versions of these things are I feel like these were priced fairly and was a good deal. Thanks

I’ve been using the KZ AZ09 adapters with my Melody IEMs for about five months now, and they’ve quickly become my go-to setup for work and daily use. The bass hits hard, the clarity is excellent, and they get plenty loud without distortion. No compromises in sound quality compared to wired use—they drive my IEMs effortlessly. Pairing is instant, and I’ve had zero connection drops. I’ll leave my phone in my truck and walk around a job site or warehouse, still connected clearly over 100 yards away. Battery life is phenomenal—I get multiple full workdays without needing a recharge. The charging case is simple and solid. It announces when you’re connected, and it’s never let me down. The touch controls are responsive and cover all the basics: play, pause, skip, volume. I’ve made calls with them too, and the mic quality is surprisingly crisp—no one’s ever complained. They’re also ridiculously comfortable and secure. I forget I’m wearing them most days, even after hours of moving around. The build quality is legit—they’re sturdy, not flimsy, and they’ve survived multiple drops without a hiccup. At this price, the AZ09s are a no-brainer. If you’ve got a favorite pair of IEMs and want to go wireless without losing sound quality or reliability, these are absolutely worth their weight in gold. ⸻ ✅ Pros: • Fantastic bass and clarity • Incredible Bluetooth range (100+ yards) • Long battery life (multi-day use) • Reliable, quick pairing • Comfortable and secure all-day wear • Durable build—survives drops ❌ Cons: • None that I’ve encountered

removing 1 star. I cannot turn off the flashing bluetooth lights, which wake my wife up in bed at night. so i'm removing one star down to 3 stars, since i'm now limited to using them only during daytime. this goes back to needing an app to control things like voice, permanent set equalizer, and LED. I had a pair of panasonic earbuds, that i really didn't like oveall due to fit (constantly falling out of ears) and flat sound, but at least i could turn off the dang LEDs. I'm using this with KZ ZSN Pro Dual Drivers 1BA 1DD in Ear Earphones. They paired easily and quickly with my phone so yipee. I do wish they had a dedicated app for permanent equalizer adjustments similar to fiio (but my fiios broke after 3 days so they're out). the "turn on" "turn off" "disconnected" "connected" "performance mode" voice over lhas a hilariously bad stereotypical asian accent, and it is crazy loud. i try to keep my headphones off my head until after i've turned them on, or take them off before i turn them off because the voiceover is sooo loud. unfortunatly there isn't any warning before you get blasted with the "low power" voice -over. so that one hurts. They have a sleek 3 fast click performance mode feature that helps the earbuds sound better. i'm not sure if this simply uses more juice to power the drivers tighter or if it changes volume and equalizer settings, but it does have a nice effect on the quality of the buds i'm using with this set. The wrap around cord is comfortable for me, and stays in place very well. i've done gardening and other active things, and haven't felt them slipping off at all, and haven't had any fit induced discomfort. I intended to use them bicycling with a helmet but haven't yet, so cannot comment. I would like a bit more control on the device, and here is where i bring the review back from 5 to only 4 stars. only 1 button per ear, the buttons control on/off (long press) pause/start (1 click) ....3 clicks gives you performance mode. 2 clicks left/right ear gives you advance or rewind to next/previous song. no volume controls, that needs to happen from the source, like your phone. I LOVED this feature on my fiios, with the ear dials, fantastic, but not here. there isn't an app for volume or equalizer control at least not one that i could download. i saw some sites elude to the existence of an app, and i even tried to download one from a link i was hopeful for but it just sat there, and i worry that i just downloaded some malware. (nothing bad noticed yet, but maybe it's just monitoring things for a while....intrusive thoughts i know). with better controls and a MUCH quieter voice over (even with the bad accent) i'd give this 5 stars.

I've purchased 6 KZ IEMs, the bluetooth cable for "paragraph b" connectors, and a dozen wired cables previously. I love the IEMs, but got tired of the cables wearing out quickly. So I upgraded to KZ IEMs with the newer "paragraph c" connector, and got this Bluetooth charging case. From the beginning, the right battery/earhook would only occasionally charge. I had a lot on my plate, and assumed I was doing something wrong, because it worked maybe 1/10 times. I just put the left battery and IEM in naturally, and it always works. I checked both sets of contacts for the right battery, and came to regularly try taking it out and placing it back in as the manual says, as we'll as wiggling the right battery and IEM around in it's compartment, and pressing the battery down in the compartment to make sure the contacts connected. That didn't change the fact it would only charge 1/10 times. I tried only charging the earhooks with the case also charging via USB-C, and only charging both battery/earhooks at the same time, even though the instructions don't say you have to, and even imply you can charge them seperately. Those didn't work either. Today I finally put them in at a time when I had nothing else to do, and experienced the same issue as always, and thought I'd leave a review. If this charging case has issues, don't try to troubleshoot them yourself. Just return them in the return window. I should also mention that the bluetooth does well through a room. But the manual states you should have your phone on the same side as your earhook, I am assuming when the connected device you are playing from is in your pocket. Obviously when you're wearing both earhooks your device can't be on both sides of your body at the same time. I have found silly things block the bluetooth for the earhooks compared even to very old bluetooth headphones. Sometimes I lay with my arm over an ear, and it cuts out. One time I was just sitting around and it was cutting out, and in that one occasion, even holding the phone right up to one earhook didn't allow for stable audio. Just test them thoroughly while you can still return them.

Works perfectly. It's comfy and has a good grip on my ear, no chance of it falling out. Battery lasts a long time. Charging case is nice too. My only problem with it is the flashing light when pairing is a bit too bright. I was worried about choppy/poor audio, but it turns out it was a problem with my computer's bluetooth usb dongle. It works fine when paired to my phone.

I just ordered a second one. Sound quality for Bluetooth is INCREDIBLE!!! I’ve been using with the castor pro bass edition. At 1st I was iffy, but there was a slight learning curve for me. A hidden feature boost volume and performance by pressing the left button 3x. If you own an iPhone as I do, don’t mess with buying the pro version of the az09, because the difference isn’t worth the extra $20.00. The regular version is AMAZING!!! I’ve been using it nonstop with no issues AT All. I own the AirPod pro gen 2 and listening to music with this is 3x better than those. The battery life is good for me. I think the longest I’ve used them straight is about 4hr with no problem. Had them for about 3 weeks at this point and only charged the case twice so far. They seem to have a nice build quality, no issues in that area either. For the price $ in my honest opinion I don’t think you’ll find any better bt adapters for iem’s like this. I bought my first pair for $30.00 then noticed them on sale for $24.00 and said yep, I’ll order a back up pair just in case. All boxes check for me though sound quality awesome, noise floor almost non existent. Good battery life. Nice range, about 30 feet. Good build quality 👍🏻 and the mic works good on phone calls as well.

Have turned my IEMs into amazing earphones. They connect well. Make sure that they've been disconnected from every other Bluetooth. A minor niggle is that they have very short range. Otherwise they're fantastic

Bom

Just what I was looking for, Quality seems good, as is the sound,

Overall a good product, but the one thing bugging me is when I have the volume low and on AAC codec which is the highest quality on android it will cut out quieter frequencies. Otherwise, it works well with my KZ ZSN PRO X's with huge range, sound quality that sounds the same as wired except for the issue I mentioned which happens below half volume.