Raynor Miranda Black Multi-Function High-Back Chair, passive ergonomics boost comfort and productivity. High-performance options let you lean back or forward effortlessly while the chair provides continuing support. 1-touch seat-height adjustment for proper posture. Pneumatic lift makes it easy to adjust seat height to minimize fatigue and muscle strain. With the flip of a lever, you can position the chair to maintain your calves and thighs at a healthful 90° angle, feet flat on the floor.