Contemporary Mid-Back Task Office Chair Ventilated Mesh Back with Built-In Lumbar Support Padded Mesh Upholstered Seat and Flip-Up Arms Pneumatic Height Adjustable 360 Swivel Waterfall Seat Tilt Lock Mechanism rocks/tilts the chair and locks in an upright position Tilt Tension Adjustment Knob adjusts the chair's backward tilt resistance Heavy Duty Nylon Base with Transparent Roller Wheels Clean with Solvent Based Cleaner No Water Needed Assembles in Under 30 Minutes with Included Materials