SPACE  Air Grid Mid-Back Swivel Chair, Black, 20-1/2 x 19-1/2 x 42h Breathable Air Grid mesh offers strong support for seated tasks. 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.