End Mill Holder, CAT 40, Dbl, 1 Review June 15, 2018August 29, 2018 - LoudMandarin Parlec C40-37Em1 ,Cnc End Mill Holder , Cat 40 ,Bore Diameter :0.37500″Hole Dia : 3/8″Shank Taper : 40Nose Dia : 1.0000 ”