The Alvin Zephyr Manager's Chair is for those who like fresh air on their back when sitting for long periods of time. This attractive design has a sophisticated rocking mechanism that allows the seat to tilt automatically as the back rocks with 2:1 synchronization. For every 2 degrees that the back reclines, the seat automatically tilts 1 degree. The rocking tension is easy to adjust or the chair can be locked into the upright position. Comfortable molded foam seat is 20" w x 19" d x 3-1/2" thick. It comes complete with padded armrests that are width and height adjustable with seven positions, pneumatic height adjustment from 19" to 24" and a 26" diameter reinforced nylon base with hooded casters. The depth-adjustable backrest is made from high-grade polypropylene that is 20" wide and rises 20" above the seat.