Excellent chair, very nice quality, well worth the money and then some, the lack of a headrest is noticeable only if you want to look up at a screen; otherwise I don't think it would be bothersome, and even then the backrest function that rises upward does the job of the headrest quite well. Very comfortable and its fabric lets the skin breathe as much as possible

Owner of the chair for about 3 days. Former owner of a chair brand "Whatever". 5 stars and if I could give more, I would. More details below:
1. Assembly: The chair comes in 8-10 pieces and is very easy to assemble with 10 simple steps, which are explained by the very detailed instructions easily, simply, without any confusion or searching. My wife did the assembly.

(From here on, it is worth noting that I am 28 years old, 1.70m tall, about 110kg with an 8mm herniated disc and back issues.)

2. Chair posture, seat, back, waist, head, arms:
Generally, for about 7 years I have been working in IT companies, spending many hours sitting in office chairs. The experience this particular chair offers, I have never encountered in any office at any company.
The sitting posture at 90 degrees is exactly as it should be to relieve the lower back and back. The two lumbar pillows with springs follow you however you sit and always keep your waist in the correct position everywhere.

The back of the chair (above the two pillows) fits exactly on the upper part of the back while the back itself is also a pillow for the head.
Here, be careful: in a sitting position, you cannot rest your head on the back as when you lean back it is slightly raised and is not very comfortable (for me), so only in a resting position does it sit perfectly on the headrest.

The seat is amazing, it moves forward and backward like a car seat (about 4-5cm travel) and you can adjust it according to your needs and height. Here, it should be mentioned that when you recline, the seat reclines with you... that is, it follows the back so your tailbone doesn't hurt.

The chair's recline has a range from about 90 degrees to 150 degrees, feeling like 160 to 170 degrees. To understand what I mean, when you recline the chair to the maximum, it's like you're a bit more upright than when you sleep. The combination of the seat and the 2 lumbar pillows that follow you as if they're stuck to you is a very remarkable experience because in any position you lock the chair, it is always relieving with zero pain. Truly an incredible experience.

The arms are also attached and follow you in any position. You can do whatever you want with them, at any height you want, generally they are 4D so they do everything. Generally, I don't use them so they don't bother me and I don't bother them. Where I do use them is when I recline and hold my phone, and they are quite convenient.

3. The negatives:
The chair is exclusively for serious consumers who want to invest in their back and waist.

The arms look a bit fake and have a bit of wobble but that's not a reason to deduct stars from the chair.

The two pillows, because they are permanently attached to you, when you make a small lift to get a good position in the chair, they pull up your shirt and it bothers me a bit... obviously this is something personal which is not worth deducting stars from the chair, the solution is to dress like Obelix, wear sweatshirts and whatever else inside your pants and problem solved.

4. Conclusions:

I got the chair for 230 euros including shipping. The truth is that at first I was hesitant because I read the review of a member named @zeppos. I'm not saying that what the person mentions is not true, however, personally, I did not find many of these in the chair.
What I can definitely say is that overall the chair is value for money, there has been a study on body posture and this study has been applied 200% on this chair. It is incredibly comfortable and quite convenient. Finally, after about 8 years of sedentary work, I get up from the chair without thinking about getting up slowly so my back doesn't hurt, something which, personally, is priceless.

P.S. As I reread what I wrote, it was like I was advertising the chair. So, for the record, I was not paid for this review.

I've had it for a month now. I hadn't had another chair of this kind before, I had a Markus from Ikea before. I would say it helps a lot with correct posture. It forces you to sit properly. It's not a couch where you can sit however you want. However, I would say it really helps reduce back pain, etc. Specifically, I would say when I feel a bit of pain in my back, I sit for 1-2 hours and I get up feeling better. I would say 5/5 but I deduct one because for some people it might not be ideal. Anyway, if you want a chair to sit however you want, then this is not for you.

Very good chair for its price. Lightweight, the mesh breathes well and you don't get hot after hours in front of the computer.

It has several adjustments — height, armrests, tilt — so you can set it up to your liking. The lumbar support is not adjustable, but it uses springs that "hug" your lower back dynamically, so it adapts itself depending on your posture. It takes a little time to find the right overall settings, but after that you can sit comfortably for a long time.

One star less because the assembly could be easier, but nothing dramatic.