THIS ITEM IS AN ISCAR 3190616 F135/90AC MILL. KEY SPECIFICATIONS INCLUDE AN INNER ARBOR HOLE DIAMETER OF 1” AND AN OUTER ARBOR HOLE DIAMETER OF 2”. THE FACE SIDE FEATURES A .75” HOLE. THE OVERALL HEIGHT OF THE MILL IS 2.5”, AND IT MEASURES APPROXIMATELY 3.3” WIDE ON THE FACE SIDE.