Headrest Height Adjustment Seat Height Adjustment Hold the frame of headrest with both hands, pull up or down to adjust the height.The adjustable range would be 100mm. Lift up the lever on the right front of seat cushion can raise or lower the seat height.Lift lever up to raise the seat height while taking your weight off chair.Lift lever up to lower the seat height while seated.The most suitable height could be achieved when the angle of knees is slightly less than 90o and feet are level with the floor. Stage Less Memory Position Locking Lumbar Support Height Adjustment Push the backwards tilting handle with right hand to unlock position, unlock the backrest tilting when hear the "click "sound;Then recline to the desired position,push the handle forward to lock position,the backrest tilt angle can be stopped at the ideal position. Hold the control handles of lumbar support with hands,pull up or down to adjust the height.There are 8 level adjustments to give you best comfort height.