The 135 split point is self-centering and reduces thrust.
and Drill set comes in a plastic pouch case. 1/4" - 1/2" Cobalt Heavy Duty Jobber Length Drill Bit Set, Drill Bit Finish: Gold Set includes 5 drill bits from 1/4 to 1/2 Sizes in the set include: 1/4", 5/16", 3/8", 7/16" and 1/2".Heavy Duty 135 Split Point, Cobalt Steel, Jobber Length, manufactured to National Aerospace standard 907. These drill bits display high red hardness, permitting speeds up to 30% greater than with conventional M2 high speed steel, and are especially effective in drilling tough, high tensile strength materials like stainless steel, inconel, and titanium.