This Autographed 3x5 Index Card with the inscription of "Balto Colts, #88" has been Personally Signed by John Mackey of the Baltimore Colts. This item is 100% Authentic to include a hologram by Beckett Authentication Services. This item will come with an affixed Beckett Authentication Services (BAS) authentication sticker, which includes a scannable QR code to verify authenticity. Please note that Beckett no longer provides serial-numbered COA cards, and the attached BAS sticker will serve as the complete authentication for this item. The authenticity can be verified on Beckett Authentication Services website.