0000 to 0.0012 in, Ring Material Grade 52100, Standards AS 9100, ISO Certified 9001, Mil-B-3990 (SAE as 39901).015 in, Ring Material Alloy Steel, System of Measurement Inch, Bore Diameter Tolerance +0.001 in, Finish Chrome Plated, Lubrication Openings Oil Holes, Outside Diameter Tolerance +0.