This CUSTOM NY Mets Black Jersey has been personally hand-signed by Young Slugging 3rd Baseman Mark Vientos. Custom Jerseys do not have any branding and are approximately XL in size. This item was signed in the presence of and witnessed by a representative of Beckett Authentication. It comes with an individually numbered, tamper evident sticker from Beckett which can be reviewed online to ensure authenticity. This process helps to ensure that the product purchased is authentic and eliminates any possibility of duplication or fraud.