This vintage box of Shefffield Durham Duplex Razor co razor blades has three blades in it. The blades are rusted and are not usable. Durham-Duplex was originally an American company, set up in New York in the late nineteenth century to manufacture the Durham-Duplex safety razor system. The blades could be re-sharpened on a strop, however, when they did become blunt they could be disposed of without the need of a new handle. A British company was registered on 11 May 1910 to advertise the safety razor, but after the First World War they planned to move into manufacturing razor blades in Sheffield. They bought shares in W & S Butcher and by 1921 they registered Wade & Butcher Ltd as a new company. This was how they acquired Butcher Works to manufacture their safety razors and blades.