Professional closed-back headphones are excellent for those who write, process, and mix. For everyone else, they will not satisfy because they are completely flat without coloring the overall sound, not even the bass. With a slight emphasis on the 2 kHz range, specifically the midrange, which I don't think will please them much. They are purely for those involved in music who want high-quality studio flat headphones to work with reliability. Now, as for the headphones themselves, I would say they are very comfortable even after hours of use. They have excellent isolation and can be used for recording without being picked up by the microphone. Their sound is classic AKG, without much bass and with a bit more "air" around 2 kHz, emphasizing the midrange. They are also quite loud without distorting. In terms of quality, they are slightly lower in terms of materials compared to the regular 371 without Bluetooth, but they had to cut corners somewhere. The headphones themselves are exactly the same in terms of quality. Now, as for the Bluetooth, the connectivity is instant, at least on the iPhone that I tried, and the sound is excellent in this case. I also tried making calls and had no issues, as they could hear me and I could hear them loudly and clearly. They come with three different cables, the familiar gold adapter, and a nice bag to store them in. In my opinion, they are worth the money. For those who may want something more, I would recommend the Focal Listen Pro, which, however, do not have Bluetooth. Happy shopping!