【Innovative Ergonomic Chair】SIHOO Doro C300L ergonomic office chair combines the latest technologies to help you maintain a comfortable posture and live a healthy lifestyle. This desk chair comes with an adjustable headrest, self-adaptive lumbar support, ultra-soft 3D armrests, a smart weight-sensing mechanism, durable and silent chair wheels, a flexible backrest, and a fully breathable mesh design, offering lasting comfort even after all day sitting. 【Dynamic Tracking System】The backrest of the SIHOO ergonomic office chair features a fully breathable mesh design and a flexible triangular frame, conforming to your back as you move your upper body from side to side. The backrest of the home high back office chair has a four-position adjustment, allowing for 6cm (2.36") of up and down movement, making it suitable for individuals of varying heights. When adjusted to the highest position, it automatically returns to the lowest level. 【Self-Adaptive Lumbar Support & 3D Coordinated Armrests】When seated in the SIHOO Doro C300L computer chair, the self-adaptive lumbar support automatically moves with your body, and the ergonomic office chair provides continuous support and comfort to your lower back, effectively alleviating back pain and protecting your health. The desk chair's 3D armrests adjust in three directions and synchronize when you recline, allowing you to relax your arms in all positions. 【Intelligent weight-sensing mechanism】SIHOO Doro C300L office chair for home features an intelligent weight-sensing mechanism that allows our chair to support up to 150 kg, adapting to the user's weight while ensuring an effortlessly balanced reclining experience. Our computer desk chair can be tilted at 92°, 100°, and 112° angles, so you can relax and rest in comfort. 【Safety Certifications】Safety is the top priority for SIHOO office chairs. The SIHOO Doro C300L ergonomic office chair holds 12 patents, passes the EU's REACH and EN1335 standards, and has German TUV certification for safety and quality. 1. Adjustable 3D Headrest, backrest, adaptive lumbar pillow, 3Darmrests, seat height. 2. Breathable and comfortable seat cushion 3. Noise free on different kinds of floor 4. Wide usage for work, study, releax, gaming 5. Pass SGS and BIFMA testing 6.enviromental material SIHOO series office chair packages: One chair with all parts; Installation tools; User manual;Pair of protection glove