I found many different office chairs, and finally selected this office chair.  I need to sit on an office chair for a long time because of work, so I need a cushion with moderate hardness, a backrest that fits the waist, and an adjustable armrest. This office chair meets what I want. The backrest is net-mounted, so it will  be keep air Circulating in the back. And the installation is easy, it only takes 20 minutes to be installed.  I like it very much and recommend this office chair!