Avenue* Aew Series Chair, Backrest With Lumbar Curve. Backrest: 15.5 in W X 14.5 in High, Seat: Saddle-Shaped Seat With Waterfall Front, 21 in W X 19 in D X 3 in T, Base: High-Profile, Aluminum Base, 28.7 in Diameter; Seat Height: 17 in -22 in, Black Vinyl Casters