Ergonomic Backrest Design: Curved backrest of this mesh desk chair can flawlessly line up with human body curve, and the lumbar support system resembles a pair of hands, pushing up and supporting your back. Choose this office chair, choose comfort Solid Chair Construction: This mid-back office chair is constructed of hard-wearing polyester mesh, durable star base, solid rolling casters and SGS-certified gas cylinder. It has passed BIFMA X5.1 Test and is recommended for office use for customers under 136 kg Comfortable Armrests: The ergonomic armrests provide you with all-time support for your arms and enable you to sit more comfortably, getting rid of your fatigue after a long day’s hard work Adjustable Seat Height: The seat height of this computer mesh chair can be simply adjusted from 35cm/13.8’’ to 45cm/17.7’’ by a little push-up/press down at the lever under the seat according to your needs Star Base & 360 Degrees Wheels: Twisting and turning about is integral within the office. So this ergonomic chair adopts a stable star base and comes with 5pcs 360-degree swivel wheels, ensuring fluent and quick movement and keeping up your quick pace of work