One of the most historically significant home run baseballs you can own, this is the very one which Hall of Famer Harmon Killebrew smacked out of the park for his 536th homerun, tying Mickey Mantle on the career home run list. Killebrew would of course retire with a total of 573, but this 536th was very important to him, as you can tell from the carefully inscribed panel, which reads, “With this home run ball No. 536 I tied Mickey Mantle on the all time home run list! Harmon Killebrew, 8/29.” Blue ballpoint inscription is bold and unbled, grading “9” out of a possible 10. OAL (Cronin) baseball shows nice use and rubbed up with stadium dirt. Also written over the logo on the south panel in black felt tip is “536 / 8-29-30 Cuellar.” Accompanied by LOA.