High Precision CAT 50 END MILL Holder, Taper to Bore Runout <0.0002" Balanced G2.5 x 25,000 RPM, Made out of High Quality Chromium Steel, H5 Bore Tolerance, DIN AD+B Coolant Capabilities, Taper Shank Ground to AT3 Accuracy ( Or Better), CAT40 DRAW BAR THREADS 1"-8, 100% inspection quality control in the USA. Mirror Bright Finish Shop's Choice VETERAN OWNED........HIGHEST ACCURACY: Taper to Bore Runout < 0.0002" T.I.R.HIGHEST Tolerance: H5 or Better Bore Tolerance.COOLANT CAPABILITIES: DIN AD+B Coolant. Through Spindle and Flange.HIGH QUALITY STEEL: Made of High Quality Chromium STEEL..PRECISION BALANCED: G2.5 X 25,000 RPM CERTIFIED..High Quality Chromium SteelChinaManufacturer100% Guarantee to be Free from any Manufacturing Defects. 100% Customer Satisfaction Guarantee