Collet System ER Collet Series ER40 Shank Type Taper Shank Taper Size CAT40 Projection Decimal Inch 313 DIN Coolant option standard All Ground Body 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 Wrench not included Premium balanced to G25 At 30,000 rpm