Andis Clipper Blades are "carburized", which is a hardening process that adds carbon to the blades, making them stay sharp longer than other blades. Andis Clipper Blades have a chrome finish which will prevent rust and maintain optimum performance. Andis Clipper Blades fit all Andis detachable blade clippers as well as Oster A-5 models. Preferred blade of Kirk Stierwalt.