YATO YT-44625 metal drill sets. Intended for professional use: for drilling high-quality stainless steel, structural steel and cold-rolled steel. HSS 4241 steel ensures several times faster drilling and maintains resistance to damage and backlash while maintaining drill geometry cross blade split point with an apex angle of 135 degrees; allows drilling without pre-drilling, ensuring perfect centering When drilling hard steel, they dissipate heat quickly without burning the bits lower coefficient of friction reduces adhesion to drills and chips total length: 150 mm working length: 75 mm handle: 1/2 inch packed in plastic boxes Length [mm]: 150 Diameter [mm]: 14, 16, 18, 20 Material: HSS Purpose: Metal Handle: Cylindrical