Lorell Mesh Back Executive Chair, 27-Inch by 27-Inch by 40-1/2-Inch, Black Contemporary executive chair features an ergonomic mesh back to provide exceptional back support and prevent body heat and moisture buildup Posture mechanism/lock adjusts the back angle independently of fabric seat and can be locked in an infinite number of positions Other functions include pneumatic seat-height adjustment, 360-degree swivel, tilt, tilt tension and tilt lock