This office Chair is with unique layered construction with continuous comfort zones orf breathable sport mesh fabric. Adjustable features offers comfort and support. Arm height adjustment allows the user to raise or lower the arms to help prevent shoulder strain. Seat height adjust function customize the seat height so your knees are at a 90 degree angle for proper circulation. Tension adjust knob adjusts the amount of pressure needed to recline the seat back. Tilt-lock allows the seat to recline or remain locked in place for your own personal comfort. Waterfall seat edge lessens pressure on legs to reduce overall fatigue.