Dak Prescott Autographed/Signed Dallas Cowboys 16x20 Photo BAS 28670 PF The number in the listing title is just an inventory sku for our records and is not the authentication number. This is an officially licensed 16x20 photo that was personally autographed by Dak Prescott. Includes a certificate of authenticity from Beckett Authentication Services (BAS) and Denver Autographs.