1960s Mies van der Rohe Knoll Flat Bar Brno Chair Stainless and Leather 4x Avail

These are Brno Armchairs, model MR50, initially designed by Ludwig Mies van der Rohe and Lily Reich in 1929. These particular examples were produced by Knoll in the 1960s. They could either be used as/is or reupholstered.

eBay