Quality material: Manufactured from M35 cobalt steel, with molybdenum and cobalt added to creates a hardened alloy, measuring Rockwell hardness up to 67, for much faster cutting and extra longer life span, with up to twelve times when compared with an average HSS drill bit. Precision treatment makes drills durable toughness, withstands heavy duty operation, resists corrosion and lubricates the drill bits better for cutting smoothly.,Quality material: Manufactured from M35 cobalt steel, with molybdenum and cobalt added to creates