Pair of vintage armchairs swivelling in lucite 1970s

Two armchairs with spring-return system, similar to the Champagne model made in 1957 by Estelle (1915-1997) and Erwine Laverne (1909-2003), two American furniture designers in vogue in the 1960s and 1970s. Lucite shell with original marbled tawny leather cushion. Each armchair rests on a swivel cast iron foot.