Precision Keyless Drill Chuck,Self Tightening, Heat Treated and ground within very tight tolerances Precision ground, Made of high quality Steel,4000 RPM, To be used in Drilling Tools, Milling Machines, Lathes, Jig Borers and Radial Drilling Machines??HIGHEST ACCURACY: Precision Ground Standard Accuracy??HIGHEST TOLERANCE: Runout < 0.005"-0.006"??Tightening: Self Tightening??Tolerance: Ground to very tight tolerances??HIGH QUALITY STEEL: Made of High Quality Hardened STEEL..High Quality SteelChinaManufacturer100% Guarantee to be Free from any Manufacturing Defects. 100% Customer Satisfaction Guarantee