Set of 4 Mid-Century Bird Chairs Model 420c designed by Harry Bertoia for Knoll international , 1960sSet of 4 Mid Century Bird Chairs Model 420c designed by Harry Bertoia for Knoll international , 1960s the stunning 420c model chairs by Harry Bertoia are emblematic pieces of modern design. Designed in the 1960s, these chairs perfectly illustrate the minimalist and functional aesthetic characteristic of Bertoia's style. This suite of four chairs with threading structure in black and white chromed steel, characteristic of its work, has an air and