This baseball has been personally hand-signed by Jacob deGrom with the inscription "18-19 NL CY." It has been obtained under the auspices of the MLB Authentication Program and can be verified by its numbered hologram at MLB.com. It also comes with an individually numbered, tamper-evident hologram from Fanatics Authentic. To ensure authenticity, the hologram can be reviewed online. This process helps to ensure that the product purchased is authentic and eliminates any possibility of duplication or fraud.