【Solid Chair Construction】This mid-back office chair is constructed of hard-wearing nylon 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 100 kg.【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 we adopt a stable star base and equip it with 5pcs 360-degree swivel wheels, ensuring fluent and quick movement and keeping up your quick pace of work.【Breathable Mid-back Design】Featuring densely knitted mesh backrest, this mesh office chair allows better airflow, accelerating heat and moisture dissipation. Mid-back design supports your spine's natural curve and protects your lower and middle back as it prompts you to sit straight.【Easy Assembly Required】We provide all the necessary hardware and tools, and illustrated instructions to help you set up this pair of chairs. Should you have any questions, please feel free to contact us!.