United Chair High-Back Adjustable Height Swivel Lumbar Support Mesh Office Chair, Black (UOC-8011) Design: 360 degree swivel and multi-direction wheel move smoothly on floor Function: the whole chair can rocked back and forth which is suitable for napping and seating during busy working days One touch pneumatic seat height adjustment Heavy duty nylon base with dual wheel carpet casters Ergonomically designed perfectly provide you have an extremely comfortable during busy working days