Tilt Mechanism: Leaning back and forward feature enables you to relax your back and shoulders The tilt tension can be adjusted using the knob under the chair There is a handle under chair to lock any angle of the back Adjustable Seat Height: The sitting height can be lifted up and down with a handle under the chair Adjust to different desks heights and meet sitting preferences SGS certified gas pump ensures safe in use Upgraded PU Casters: 360-degree swivel casters made from good PU material Noiseless on move and floor friendly Chair legs are BIFMA certified