Milling Chuck Taper Size BT40 Hole Dia 3/4 in Nose Dia 2.1900 in Projection 3.6400 in Coolant Fed Coolant Through Bore Depth 2.2400 in Features 56 to 60 HRC Flange-Entry Coolant is the Same as DIN Form B Shiny Taper with Black Oxide Finish for the Best Combination of Accuracy and Durability