HSS Twist Drill Bits Set Jobber Length, Parabolic Flute, Gold/Black, 135 Deg. Split Point, 3-Flat Shank, Ideal on Mild Steel, Metal, Iron, Copper..MATERIAL: Premium High Speed Steel Keeps High Hardness and Strength for Long Life Drilling;UNIQUE FLUTE: Parabolic Flute Design Enable Easy and Quick Penetration and Chips Removal;POINT ANGLE: 135 Degree Split Point Prevents Drill from walking, Better Self-Centering and Reduce Thrust;SPECIAL SHANK: 3-Flat Shank Eables Tight and Easy Chuck without Slippage During Application ;APPLICATION: Drill Holes in Hard Metal, Steel, Iron, Zinc-Alloy, Metal Sheet, Steel Plate, Copper..etc.