Space 5560 Space Air Grid Deluxe Task Chair, 20-1/2w x 19-1/2d x 42h, Black Built-in lumbar support helps reduce back pain. 2-to-1 synchro-tilt allows user to adjusts back and seat angle together. Wheels are specially designed for carpet use. Casters supplied with this chair are not suitable for all floor types. Alternative casters are available to meet your specific needs.