Ergonomic Height-Adjustable Design: The seat height of this office chair can be adjusted within the range of 17''-21'', which makes it convenient for different people to use. It is perfect to match up with ergonomic standing desk as well. Composed of advanced gas rod, it can be lifted up and down with great stability. Rocking Backrest with Lumbar Support: Considering that you may need a leisure time throughout a long working day, the executive chair is designed with comfortable rocking function. More, there is an adjustable lumbar support to relax your spine muscle for higher comfortableness.