Monster Tool Company 5/16 x 2-1/2 RH w/CR Carbide Boring Bar, 74339, Features: Mirror polished cutting surface and a 4RMS finish, Lock down flat on shank automatically locates tool on center, NC Generation / BB Series, Made in the USA, 5/16, MinBore: .290, MaxBore: .900, Projection: .073, Material Base: Carbide, Finish / Coating: Uncoated, MPN: 74339, PKG QTY: 1 PC