Manufactured from a premium grade of M-7N molybdenum high speed steel. the Nitro Heavy Duty 135 degree Split Point drill with a Nitride surface treatment, that give a hard, protective layer to the drill (increases hardness without increasing brittleness), which is measurably harder than high speed steel. Body and clearance are gold and black surface treated for maximum lubricity. Recommended for use in stainless steel and other hard metal drilling.