ThunderBit® Reduced Shank Drill, Heavy Duty High Performance, Series: T8HD, 25/64 in Drill - Fraction, 0.3906 in Drill - Decimal Inch, 5-1/8 in Overall Length, 3-3/4 in Cutting Depth, Spiral Flute, 3-3/4 in Flute Length, 3/8 in Shank, Reduced Shank, 135 deg Point, Split/Self-Centering Point, HSS Cutting Edge, HSS, Black/Bronze Oxide, Applicable Materials: Alloy Steel, Cast Iron, Low and Medium Carbon Steel, High Alloy Steel, Steel, Stainless Steel, PH Steel, Tough, Medium and High Tensile Strength Alloy