The 8512NB Multi-Function Mid-Back Chair features: Contour Molded Seat and Back with Built-in Lumbar Support /Choice of Custom Fabric Seat and Back /Ratchet Back Height Adjustment /One Touch Pneumatic Seat Height Adjustment /Multi Function Control with Forward Tilt with Adjustable Tilt Tension /Seat Slider Adjustment /Height and Width Adjustable Arms with Soft PU Pads /Heavy Duty Nylon Base with Dual Wheel Carpet Casters /GREENGUARD Indoor Air Quality Certified