??High Precision R8 END MILL Holder?? Taper to Bore Runout <0.0001" ?? Made out of High Quality Chromium steel ?? H7 Bore Tolerance ?? DRAW BAR THREADS 7/16"-20, 100% inspection quality control in the USA ?? Shop's Choice™ VETERAN OWNED........??HIGHEST ACCURACY: Taper to Bore Runout < 0.0001" T.I.R.??HIGHEST TOLERACE: H7 or Better Bore Tolerance.??COOLANT CAPABILITIES: Through Spindle.??HIGH QUALITY STEEL: Made of High Quality STEEL..??Draw Bar Thread: 7/16" - 20.High Quality SteelChinaManufacturer100% Guarantee to be Free from any Manufacturing Defects. 100% Customer Satisfaction Guarantee