This end mill holder tapers ground to AT3 or better for exceptional precision and performance. Features include through-spindle coolant and maximum TIR of 0.0002 O.D. to I.D. This listing is for each. Technical Specification Item End Mill Holder Dimension Type Decimal Inch Taper Size CAT40 Bore Dia. 1.5000′ Projection 4.62′ Nose Dia. 2.620′ Bore Depth 2.38′ End Single