Constructed of M-42 8 percent cobalt high speed steel for super abrasive resistance in tough metals. Heavy duty spiral flute design produces faster chip ejection.Shorter cutting tip reduces torque for drilling in high tensile strength materials. 135 degree split point reduces feed pressure for easier penetration without work hardening. Ideal for use with screw extractors. Sizes: 5/64", 7/64", 5/32", 1/4" and 19/64.