The most necessary and successful element of this impressive chair is the lumbar support. I have injured my back twice, and this chair makes sitting for prolonged periods not only possible but also comfortable. It is possible to adjust the overall height to an infinite number of positions securely, without pre-established choices dictated to the user. The three positions for angling the seat back are very useful for me: 1) straight up, for intense work, 2) very slightly tilted back, for overseeing your work with intermittent adjustments, and 3) more tilted back, for watching comfortably without working. It is fantastically solid, suggesting great durability. The only very small quibble I have is that the arm rests, while very comfortable and adjustable, tend to move easily from their selected positions. I would prefer that they be more firm, requiring a deliberate effort to change their positions. Overall, an enthusiastic BRAVO!