'Drill Bushing, Head Press Fit, Inside Dia. 10mm, Outside Dia. 5/8 In., Inside Dia. Tolerance +.0001- +.0005 In., Outside Dia. Tolerance +0.0017 - +0.0014 In., Concentricity Tolerance .0003 In. T.I.R. Max, Overall Length 3/8 In., Material 52100 Thru Hardened, Finish STEEL, Drill Size 10.00mm, Hardness RC 62-64'