Mesh Office Chair with Tilting Backrest and Retractable Footrest-GrayTilting backrest for free rocking from 90 to 120 and can be locked at any angle Double back structure combines a small upper backrest and a lower lumbar support Scientific 2D headrest for optimal support to reduce head and neck fatigue Has a 3D adjustable armrests allowing you to find your most comfortable position Retractable footrest allows you to freely stretch legs for better relaxation Waterfall seat surface can adapt to your hip curves for