Mid-century Dorsal office chair, designed in 1980 by Emilio Ambas and Giancarlo Piretti for the Italian company Openark.Mid century Dorsal office chair, designed in 1980 by Emilio Ambas and Giancarlo Piretti for the Italian company Openark. The Argentinian Italian duo has been working together since the late 1970s and, alongside the Dorsal armchair, created another ergonomic armchair called the Wirbel. Piretti is known for its collaboration with the Italian company Castelli. The frame of the chair is a combination of steel and plastic, the top half of the back is