TaskMaster Hard Floor CastersShown with optional Hard Floor Casters, sold separately. Pneumatically adjusts 8" up or down while seated. Overall height adjusts 19" to 27". Contoured, black polyurethane self-skinning foam seat and back won't crack or peel with wear. Large nylon reinforced base with 20" diameter chrome-plated adjustable footring and 2" high-impact nylon-reinforced glides. Backrest adjusts 3" in height and depth. Seat: 16-1/4w x 16-1/4d. Color: Black.