ERGONOMIC LUMBAR SUPPORT - With a thoughtfully constructed contemporary conference chair with ribbed seating, appreciate comfortable luxury. Features a naturally designed shell back which imitates the shape of a human back. Experience lumbar ergonomic comfort from the comfortably reinforced cushioning foam. Tilt Mechanism 360 ROTATING SWIVEL CASTORS- For smooth, comfortable, and pleasant rolling throughout your workplace and preventing scratches on your floor, 360 ° swivel plastic casters; rotatable seats are convenient for you to move around and for multi-tasking.