Collet System Single Angle Collet Series TG100 Shank Type Taper Shank Taper Size BT50 Projection Decimal Inch 4 DIN coolant through the flange Shank traverse ground to obtain optimum accuracy Meets or exceeds ANSI specifications 00002 or better ensures the best possible cutting tool life Wrench not included Factory Balanced to save spindle life, tool life and increased productivity Threaded through holes for a backup screw tool stop or coolant through when removed BT3040 Premium balanced to 20,000 rpm BT50 Premium balanced to 15,000 rpm