THIS NORTON GRINDING STONE, SIZE 2/1-5/8 X 2 X 5/16, IS A HIGH-QUALITY ACCESSORY DESIGNED FOR PRECISION TOOLING TASKS. IT IS AVAILABLE IN A LOT OF 12 UNITS. TECHNICAL SPECIFICATIONS INCLUDE A MAXIMUM RPM OF 11460 AND AN OVERALL LENGTH (OAL) OF 2.06IN. THE DIMENSIONS ARE FURTHER SPECIFIED WITH AN OUTER DIAMETER UPPER OF 2IN AND AN OUTER DIAMETER LOWER OF 1.67IN. THE INNER DIAMETER UPPER IS 1.15IN, AND THE INNER DIAMETER LOWER IS 5/16IN.