Constructed of m-42 8% Cobalt high speed steel for super abrasive resistance in tough metals. Heavy-duty spiral flute design produces faster chip Ejection. Shorter cutting lips reduce torque for drilling in high-tensile strength materials. 135 split point reduces feed pressure for easier penetration without work hardening. No. 3016004: 1/16" No. 3016005: 5/64" No. 3016006: 3/32" No. 3016007: 7/64" No. 3016008: 1/8" No. 3016009: 9/64" No. 3016010: 5/32" No. 3016011: 11/64" No. 3016012: 3/16" No. 3016013: 13/.