Vertagear Racing Series S-Line SL2000 Ergonomic Office Chair - Black/Carbon (Rev. 2) Reinforced 5 star base: Redesigned and constructed from a heavy-duty alloy material Effortless assembly: "Slide-In design creates a quick one-person installation process Steel frame and high density resilience foam Tilting feature with adjustable resistance and locking system Custom racing stylist Penta rs1 casters coated with PU for soft and smooth gliding on any surface