DIXCEL DISC ROTOR TYPE HD [Compatibility List in Desc.] 1157914S-HDBrand DIXCEL Product Number 1157914S HD Product Description Model Grade:. G55 AMG _x000D_ _x000D_ HD type _x000D_ In pursuit of higher stability _x000D_ The heat treatment stabilizes the bonds between the elements in the structure of the cast iron This prevents disc distortion and strain which is common immediately after installing new discs. _x000D_ The treatment also optimizes the surface hardness, which improves brake response. _x000D_ Higher