This autographed Fanatics NBA adult men's XL jersey has been personally hand-signed by Chet Holmgren of the Oklahoma City Thunder. This autograph is certified by Beckett Authentication Services (BAS) Witness Certification. That means that a Beckett representative was present when this item was signed. It comes with the numbered authentication hologram with a QR code card that verifies the authentication on the Beckett website.It is also certified by USA Sports Marketing. It comes with the numbered hologram and matching Certificate of Authenticity.