A powdered high speed non-stainless tool steel from Crucible. It has high wear resistance and high impact toughness, making it popular for cutting competition knives. It has a higher toughness than M2, and is mainly used in custom knives, although Benchmade and Spyderco have made a few sprint runs with it. It is a high end tool steel and is fairly expensive.
1.40% Carbon (C), 4.0% Chromium (Cr), 0.30% Manganese (Mn), 5.25% Molybdenum (Mo), 0.55% Silicon (Si), 0.06% Sulphur (S), 5.50% Tungsten (W), 4.00% Vanadium (V).