With a contemporary look and ergonomic design, this chair is an ideal choice for any office or drafting environment. The height adjustable backrest features a tightly stretched silver mesh backing and ergonomically contoured design to provide good lumbar support. Pneumatic height control lets user raise and lower chair height quickly. Multiple controls for adjusting back rest tilt independently or in synchronization with seat tilt. Includes dual wheel casters and a 26" diameter polished aluminum base. Backrest is 19½"w x 19½"h. Seat cushion features long-lasting molded foam and is 19½"w x 19"d x 3" thick.Office model height adjusts from 17" to 21".Drafting model includes CK49 height extension kit and adjusts from 24½" to 28½".