Royaloak Rover Computer chair has a firm foam cushion upholstered with nylon mesh, which makes long hours at your desk comfortable. The flexible high-grade nylon mesh back is designed for air-circulation and support when you lean back the adjustable Lumbar support the lower lumbar area, it has depth tuning adjustment. Adjust the height using the gas lift to find that comfortable position and the chrome base and nylon castors make it easy to move around your space. adjustable armrest to rest your arms. this chair comes with a single lever to adjust the height and lock the backrest.