Classic Replica mid back office chair - stabilizing swivel bar and knee tilt with tensioner knob (White, Pack of 1) Ribbed White Mid Back Office Chair, Back and seat with PU padding and backing Stabilizing bar swivel (360-Degree rotation), fully adjustable height and knee tilt with tensioner knob. Sturdy, heavy-duty pyramid chrome base with white capped covered nylon wheels  slip resistant on most floors and carpets. Fire retardant foam  California standard CA117