Great product! I am a student pilot and already had the Sony XM4s. Decided to invest in this microphone based on reviews and the overall cost seeming much less than investing in a headset with similar features. It worked right out of the box and was just plug and play. My attachment didn't really fit my headphones and the part of the clip snapped off but it still stays on my headphones securely and the magnet was strong enough to hold the microphone in place.As for the headphones, I didn't even use noise cancelling because I find it very useful to be able to hear the engine while doing maneuvers. I could hear my instructor and ATC just fine but if needed, noise cancelling did work as expected. So its still a very solid headset if the battery were to die mid flight.If you are looking for a way to make your normal headphones (Sony XM4s for me) work double-time, I think this is a fantastic solution!To date i have flown on about 5 flights with the new setup. I fly the 747, and this is where I am using the mic. I absolutely love this setup! The mic boom picks up my voice perfectly. The octagonal shape of the magnets is a nice design. The sound quality is outstanding and the boom mic picks up my voice from a good distance when the boom is away from my mouth. No issues with ATC trying to understand me. The boom is perfect length, and a perfect thickness. The whole setup feels sturdy and like it's built to last. The mic does not drift. I believe your change to a single boom piece instead of the two pieces on your previous model has improved this dramatically. That boom stays in place just fine now.The bluetooth setup is awesome! It works extremely well and seems to last a good time on the battery. I wasn't sure what to expect with the volume vs ATC or hotmic with the other pilot. I wasn't sure if it would meter up and down based on incoming transmissions. It does not meter, but its' volume is easily controlled and does not interfere with any other transmissions. Again in my opinion you have nailed it with that design. I did notice it did not come with a charging cable, but that was not an issue as I have many micro USB cables around.The carrying case is perfect size for everything.. It holds everything great for the setup and love that it has an internal pocket. The Bose case the headphones come with, lacks and internal pocket which drove me nuts, and is way to small to try and cram all the wires and setup inside.I had a couple other pilots try out my headset. They were extremely impressed. They were using the Bose A-20s, and said your design is the most practical option they have seen that comes close to that quality. My favorite design feature is the ability to switch the boom from one headphone side to the other. This is handy when I am sitting IRO duty and switch between the left and right seat. Your design allows for the headphones to be worn the correct way (some guys just flip there around depending on what seat they are in, but this results in wearing the headphones backwards sometimes). The pins for the GA adapter seem to be well made, and the cord length is perfect. I like that you include a clip to aid in keeping the excess cord out of the way.Well done...Highly Recommended!My headset Sony XM4.I checked online and wrote to seller if he will send the mic attachent and he confirmed.I was really excited to use this, but only was disappointed.As you can see from the above pictures, the mic attachment (the U) that should fit on the left ear cup of Sony xm4, does not fit. Hence the hole does not align and the mic jack won't go in.I tried this on a B777. Mic and wires quality is good. But after paying 259$ and not been able to use it because of the attachment was not appreciated. For the price paid for the headset, a quality was expected but not met.The attachment needs to be simple to attach and remove.Doing long hauls with augmented crew means, the need to change/remove headset during rest times. During those times, the attachment should be able to remove easily, so the headset can be used for music and then back again when you in the cockpit for work.The attachment is not made from a durable material and was cracked. With continuous use of removing and attaching again, it will not last.I called on the number given on website, I wrote on amazon questions, and also wrote a email. Got no response on any. Hence returned the product for a refund.Would have liked a prompt reply from seller, since I was traveling and was on a pattern in usa, so if any replacement of the attachment I could have tried, while I was in the USA.But since I left back to other destination, there was no point waiting and carrying a useless headset wires and attachment in the bag.I ordered this Dec 3, 2019. It's now September 8, 2020. I'm a Challenger 325 pilot, and we didn't fly much from February to July. We don't fly a lot - about 260 hours a year - so not a heavy workload placed on the Crystal Mic. The first issue I had was that I had to deface my new Bose Q35 headset with magnets to mount the crystal mic. The second issue was the number of wires and connectors (more than UflyMike and other similar aviation headset mike booms). I liked that I could move the boom from ear to ear, depending on my seat position in the aircraft. I liked the nice case that held the Crystal Mic wiring, bluetooth adapter and my Bose headset. Last month, I started getting intermittent stereo cutout (both ears), and before that, I would periodically send loud static over the interphone due to the pin connection into the mic boom. During a recent 9-leg trip, the stereo cutting out became too much and I switched to mono. A leg later, the magnet in the mic boom gave out and the boom fell off my headset, leaving me juggling radios, mic switch and mic boom until I could switch to my backup PilotUSA PA-1779. I don't recommend Crystal Mic based on the expense and my experience with this equipment.