This is an Official Spalding Baseball that has been hand signed by 25 members of the 1976 New York Yankees Team. Some of these members include: Thurman Munson, Yogi Berra, Jim Hunter, Bob Lemon, and Elston Howard. Please note, the Billy Martin signature is deemed a clubhouse signature. This item has been certified authentic by Beckett Authentication (BAS) and comes with their tamper-proof sticker and matching full-page certificate of authenticity.