This set of 2 mid-back office chairs are constructed of nylon mesh, a durable star base, solid rolling casters and SGS-certified cylinder. These office chairs features densely knitted mesh backrest, which allow better airflow and breathability, and accelerate heat and moisture dissipation. The curved mid-back design supports your spine's natural curve and protects your lower back as it prompts you to sit straight. Adjust the seat height by pushing up and down at the lever under the seat. By pulling the lever, it can be tilted and leaned backward or locked in place for various sitting positions. Twisting and turning about is integral within the office, so we adopted a reliable claw base and equipped it with 360-degree swivel wheels, ensuring fluent and quick movement to keep up your quick pace of work. Mid-Back Mesh Office Chair Ergonomic Computer Chair, Set of 2: