Sihoo M90 High-End Ergonomic Office Chair with Adaptive Lumbar Support for Different Postures 【 Comfortable Lumbar Support】 Do you have back pain? SIHOO home office chair with lumbar support will be the best choice to protect your spine from the pain and fatigue of sitting for a long time. Adaptive elastic waist support can automatically provide support strength based on body weight and contact angle. Choose this swivel chair if you always sit in the office for long 【Breathable Mesh 】 SIHOO ergonomic office chair is made of high quality breathable mesh, which provides support while ensuring air circulation, so you can stay cool and comfortable even after sitting for a long time. The high quality mesh prevents wear and tear and sudden changes, providing you with long-lasting comfort 【Highly Adjustable】 The adjustable headrest, 3D armrests and back tilt provide you with better support when you sit on our computer chair. You can choose 3 positions between 90° and 123° to tilt the backrest, or you can adjust the backrest up and down according to your height and sitting position, suitable for people from 5'5" to 6'2". 4" seat height adjustment with 360° free rotation offers enhanced convenience 【High Quality and Easy to Assemble】 The gas lift of this high back office chair has passed BIFMA and SGS certification, as well as the 2504 lbs static pressure test. Our desk chair can bear a weight of up to 330 lbs. After 3 years of research and design, M90C converges with craftsmanship to adopt a split backrest, which can more quickly disperse the pressure on the lumbar spine, to make more people can enjoy the comfortable experience brought by the ergonomic chair. Smart dynamic lumbar pillow with separate dynamic support for the lumbar spine and back, helping to release pressure on the lumbar back separately 3D armrests with back linkage to keep arms comfortable even when leaning back 6CM backrest lift for accurate support of the lumbar spine Double-joint elastic headrest , double joint adjustment for more accurate cervical support, stretch mesh for comfort and elastic 130° recline , relax and enjoy yourself during the break High quality, rigorously tested : passed BIFMA and SGS test, use safe and durable precision steel mechanism Fully Textilene fabric , breathable, elastic and waterproof A part of the home aesthetic : whether for home use or office seating, it is suitable for a variety of situations MATERIALS - Fully breathable mesh chair - Nylon + fiber adaptive lumbar support - S-shaped back frame, PP + fiber material, fit the curve of the spine - Mechanical steel multifunctional mechanism - 3D PU armrest surface - 350 aluminium alloy chair feet, passed 1136kg static pressure test - φ60 carpet casters or hard floor casters with quiet roll technology