Monster Tool Company 5/16 x 1/4 100-Deg. Single FL Carbide Countersink, 67541, Designed for general purpose countersinking, chamfering and deburring in most ferrous and non-ferrous materials, Diameter: 5/16, Number of Flutes: 1, Single End, Right Hand Cut, Included Angle: 100-Degree, Overall Length: 2-1/8, Shank Diameter: 1/4, Material Base: Carbide, Material Construction: Brazed, Finish / Coating: Uncoated, MPN: 67541, PKG QTY: 1 PC