SUTTON TOOLS® D188-Series Reduced Shank Drills are designed to increase the drilling capacity of drill chucks for large scale boring applications. These bits feature a blue surface finish which is suitable for ferrous metal drilling applications. The steam oxide finish prevents chip build-up on the cutting edges and reduces cutting friction, especially in low carbon steels. These drills should be used at low speed (350 RPM or less). Features Reduced Shank - Suits 13mm (or larger) drill chucks, 118° Standard Point - For general purpose applications, Made from M2 High Speed Steel (HSS) - Offers the best combination of strength, heat & wear resistance, Blue Surface Finish - For ferrous metal drilling applications, Specifications Diameter: 5/8" (15.88 mm), Overall Length: 152 mm (6"), Flute Length: 86 mm (3-3/8"), Reduced Shank Diameter: 12.5 mm (1/2"), Point Angle: 118° Standard,