Lubricated with a high temperature lubricant able to withstand the stresses of turning at 22,000 RPMS. Use for repairing and altering the profile of Freud router bits. Will fit most brands of router bits. Contains 1 each of: No. 62-100, 1/8" inside diameter. 3/8" bearing diameter, 5/32" bearing height. No. 62-102, 3/16" inside diameter, 3/8" bearing diameter, 1/8" bearing height. No. 62-104, 3/16" inside diameter, 1/2" bearing diameter, 3/16" bearing height. No. 62-108, 8mm inside diameter, 22mm bearing diameter, 7mm bearing height.