This is a Black Nike Chicago White Sox Jersey that has been hand signed by Ken Griffey Jr. This jersey is Size XL. This item has been witnessed and certified authentic by Beckett Authentication (BAS) and comes with their tamper-proof witness sticker. Beckett Authentication has recently changed their physical certificate card policy where they no longer match their tamper-proof sticker with a physical certificate. A certificate can be printed on Beckett's website for the matching authentication number.