Mid-back Mesh Chair features a simple synchronized mechanism for enhanced comfort & mesh back that allows air to flow freely to help keep you cool as you're seated. Separated lumbar support offers ergonomic support for your lower back to help prevent strain through extended seating. Back reclines at a 2:1 ratio to the fabric-upholstered seat. Other functions include pneumatic seat-height adjustment, 360-degree swivel, tilt with three-position tilt lock & adjustable tilt tension. Height-adjustable, plastic arms with polyurethane padding can be positioned to accommodate your personal preference. Black, five-star nylon base is equipped with smooth-rolling, dual-wheeled casters for easy mobility. Weight capacity is 275 lb. Mid-back chair meets or exceeds ANSI / BIFMA standards.