sihoo ergonomic office chair, computer desk chair with adjustable sponge lumbar support, comfortable thick cushion high back desk chair with adjustable headrest and pu armrests(black) sihoo sihoo aims to become a global professional engineering furniture supplier by providing advanced intelligent engineering design concepts for furniture for global users to learn, work and play. we have established the sihoo intelligent engineering laboratory to enable our customers to obtain high-quality products and outstanding experience, as well as a chain system that integrates design, manufacturing, marketing, quality testing, storage and installation in all industries. in order to better apply the concept of ergonomics to the chair, sihoo has spent many years of in-depth research and innovation on factors such as sitting posture and stress to achieve the best balance between the chair and the person. according to medical research, different sitting postures exert different forces on the spine, and waist health problems are also negative effects of sitting posture. lumbar spine pressure is precisely one of the health issues that sihoo designers are concerned about.