Tangkula Black Ergonomic Desk Task Office Chair High Back Office Chair Seat Size: 18.9" X 18.5" Backrest Size: 18.9" X 26.7" Adjustable Seat Height: 18"-21" Overall Dimension: 24" X 23" X44.3"-47.3" 360 Degree Swivel Wheel And Chair Can Run Smoothly On Floor