EVERYTHING. I never believed I would find this chair again. I have serious leg issues and this chair makes my 10 - 12 hr working day day COMFORTABLE. The height adjustments are suitable for all heights. So EASY to assemble...13 bolts. The armrests are the perfect height and size to keep your arms comfortable for work or gaming. Overall  not as good for lumbar support but you can always add a cushion if necessary but a GREAT comfortable and large size chair for long term use.