All Centaur Precision Tools BT & V-Flange/CAT CNC Endmill toolholders are made from high grade steel, precision ground for solid spindle contact, balanced for 22,000 RPM and concentric to 0.0002 TIR or better (AT3 fit). Centaur toolholders have fully ground flanges and V-grooves to ensure smooth, accurate handling in automatic tool changers and reduced vibration at high RPM. 100% Quality Inspected. Order now and transform your machining experience with a tool that sets the standard for excellence. https://centaurtools.com/v-fla....nge-cat-tool-holders