Scientific Headrest Height adjustable headrest for added personification of the chair to meet customers need.   Ergonomic Chair Back Waterfall chair back design fits the curve of your body perfectly for fully supporting the back, matching chassis for 90-120°tilt back supports you sitting comfortably for all day.   Ergonomic Lumbar Support PA material, Intelligent induction gravity lumbar support for adjusting the waist support to correct and protect the lumbar spine and pelvis.   Adjustable Armrests Three-dimensions adjustable armrests for rotating 36° to fully support arm and relieve shoulder pressure.   Breathable Mesh XUERexecutive office chair is made of high quality special mesh fabric, which is strong and resistant to pressure and tear, flexible and breathable, providing a relaxing sitting experience.   Sturdy Chassis The black grilled paint chassis is made of mechanically thick steel and has a four planetary line control locking, passed the American BIFMA test.   Gas Lift The three-stage gas lift is made of steel and offers 65mm adjustment. It has passed the American BIFMA test.   Nylon Chair Legs 340 black nylon chair legs are made of durable PA material, passed the American BIFMA test for letting you rest assured to use.   Thoughtful Casters Smooth and silent black nylon casters support you moving freely without worrying that the floor will be scratched and the noise will affect others.