ERGONOMIC MESH BACK TASK CHAIRS Ergonomic Mesh Back Task Chair With Air Mesh Seat Ergonomic Mesh Back Task Chairs provide a comfortable long-term seat in offices, classrooms, computer labs and more. Mesh upholstery ensures comfortable vented seating, and the adjustable lumbar panel provides customizable back support. Air Mesh seat provides breathable cushion comfort for long-term comfort seating. Seat height adjusts from 18" up to 21". Pneumatic gas lift seat height adjustment. Hooded double wheel casters allow smooth mobility.