Drill Bushing, Bushing Type Head Press Fit, Inside Dia. 0.397", Outside Dia. 3/4", Inside Dia. Tolerance +.0001- +.0005", Outside Dia. Tolerance +0.0018 - +0.0015", Concentricity Tolerance .0003" T.I.R. Max, Overall Length 1", Material 52100 Thru Hardened, Finish STEEL, Drill Size X, Hardness RC 62-64SpecificationOutside Dia. Tolerance : +0.0018 - +0.0015" Concentricity Tolerance : .0003" T.I.R. Max Overall Length : 1" Material : 52100 Thru Hardened Finish : STEEL WARNING:California ResidentsThis product can expose you to chemicals including Styrene, which is known to the State of California to cause cancer and birth defects or other reproductive harm.