Monster Tool Company 5/16 x 1/4 90-Deg. 3FL Carbide Countersink, 75189, Designed for general purpose countersinking, chamfering and deburring in most ferrous and non-ferrous materials, Diameter: 5/16, Number of Flutes: 3, Single End, Right Hand Cut, Included Angle: 90 2-7/8 1/4, Material Base: Carbide, Material Construction: Brazed, Finish / Coating:, MPN: 75189, PKG QTY: 1 PC