High Quality - SIHOO office chairs have been certified by BIFMA and SGS, passed 1000kg static pressure test. It can carry a weight of up to 150kg. Every part of this computer office chair has strict safety quality testing, cushion impact test, handrail fatigue test, chair foot static pressure test, ect. Simple instructions enable anyone to put chair together in eight simple steps! Long Hours Sitting - The mesh back and mesh seat keep air circulation for extra comfort. High quality mesh resists abrasion and transformation, , making the high back desk chair suitable for a long-day sitting of 8 hours. Meanwhile, it allows you to sit without feeling hot or sweaty. It also features easy maintenance, please wash the mesh in warm water on a gentle cycle with a cold-water rinse. Adjustable 3D Armrest -This office chair from SIHOO features 3D adjustable armrests - go forwards and back, up and down, and rotate 36o for the best fit to your favorite position. No matter in appearance or the function, it makes perfect sense of technology and future. Find the best angles for your posture. Ergonomic Design - SIHOO is recommended by Ergonomics Application Association. Ergonomic design is based on the human body dynamic digital model. The S-shaped backrest mimics the human spine which helps release the spinal pressure, with more effectively adjustable lumbar pillow to cherish. The flowed waterfall arc seating design thigh support lets you sit a more comfortably, relaxed posture.