S-18- 8 IN Chef Knife /Turbo knife steel comes from famous German steel maker ThyssenKrupp. At CHROMA we use this blue Turbo steel to make an unbelievable new knife concept. The Turbo has on the edge an HRC of 61* while the rest of the knife keeps pretty flexible at 56* HRC. KA-Six is harder and it stays hard longer. Turbo has excellent sharpness. Sharper than most knives on the market. Sharper than many Japanese brands. This way the hard Turbo is easier to resharpen. You can recognize TURBO by the metallic blue pearl. ThyssenKrupps Turbo steel passes all European Union food tests for Food Contact Materials (FCMs).