I'm 6'4" and my torso is to long for the headrest as my shoulders rub against it when it sit back in the chair. I had to remove it to keep it from digging into my shoulders.
Chair was delivered free within 2 days easy to assemble with well organized packaging. First thing i noticed were the easy rolling casters and very comfortable seat. I would reccomend for anyone wanting a comfortable and affordable office chair. The lack of back height adjustability is not noticed due to the mesh comfort and adjustable lumbar
I'm happy with the chair overall but received a defective screw and discovered it in the midst of assembling the chair. I had to purchase a replacement at a hardware store and so that was disappointing and frustrating because it delayed my being able to use the chair. The manual indicates that the arms can move front/back but that is not the case with this model; the arms can only adjust vertically. Many of the chair components are quite heavy and solid but the base is a painted silver color was scratches and looks cheap. I would have preferred a chrome base or something a bit more polished looking. The chair is really comfortable and provides great support and is comfortable. The mesh material is nice because it is breathable.
Started working from home ~8 hours a day mostly sitting tried several chairs that caused back pain and soreness tried the Hyken and it solved all my problems!! I highly recommend this chair as an affordable ergonomic solution for sitting long periods!