Every high-quality, Galfer-patented Wave® MTB/eBike 6-bolt disc rotor is made from a proprietary mix of virgin high carbon 420 stainless steel, laser cut (never stamped), double disc-parallel ground to assure perfect parallel flatness and heat treated to each specific application. Wave design comes from the Galfer motorcycle division and has been used across many disciplines at the highest level. Not compatible with Fulcrum AFS System.